diff --git a/partiql-ast/api/partiql-ast.api b/partiql-ast/api/partiql-ast.api
index 0c2783a126..688c53ecf2 100644
--- a/partiql-ast/api/partiql-ast.api
+++ b/partiql-ast/api/partiql-ast.api
@@ -14,11 +14,10 @@ public final class org/partiql/ast/Ast {
 	public static final fun excludeStepCollWildcard ()Lorg/partiql/ast/Exclude$Step$CollWildcard;
 	public static final fun excludeStepStructField (Lorg/partiql/ast/Identifier$Symbol;)Lorg/partiql/ast/Exclude$Step$StructField;
 	public static final fun excludeStepStructWildcard ()Lorg/partiql/ast/Exclude$Step$StructWildcard;
-	public static final fun exprAgg (Lorg/partiql/ast/Identifier;Ljava/util/List;Lorg/partiql/ast/SetQuantifier;)Lorg/partiql/ast/Expr$Agg;
 	public static final fun exprBagOp (Lorg/partiql/ast/SetOp;Lorg/partiql/ast/Expr;Lorg/partiql/ast/Expr;Ljava/lang/Boolean;)Lorg/partiql/ast/Expr$BagOp;
 	public static final fun exprBetween (Lorg/partiql/ast/Expr;Lorg/partiql/ast/Expr;Lorg/partiql/ast/Expr;Ljava/lang/Boolean;)Lorg/partiql/ast/Expr$Between;
 	public static final fun exprBinary (Lorg/partiql/ast/Expr$Binary$Op;Lorg/partiql/ast/Expr;Lorg/partiql/ast/Expr;)Lorg/partiql/ast/Expr$Binary;
-	public static final fun exprCall (Lorg/partiql/ast/Identifier;Ljava/util/List;)Lorg/partiql/ast/Expr$Call;
+	public static final fun exprCall (Lorg/partiql/ast/Identifier;Ljava/util/List;Lorg/partiql/ast/SetQuantifier;)Lorg/partiql/ast/Expr$Call;
 	public static final fun exprCanCast (Lorg/partiql/ast/Expr;Lorg/partiql/ast/Type;)Lorg/partiql/ast/Expr$CanCast;
 	public static final fun exprCanLosslessCast (Lorg/partiql/ast/Expr;Lorg/partiql/ast/Type;)Lorg/partiql/ast/Expr$CanLosslessCast;
 	public static final fun exprCase (Lorg/partiql/ast/Expr;Ljava/util/List;Lorg/partiql/ast/Expr;)Lorg/partiql/ast/Expr$Case;
@@ -516,29 +515,6 @@ public abstract class org/partiql/ast/Expr : org/partiql/ast/AstNode {
 	public fun accept (Lorg/partiql/ast/visitor/AstVisitor;Ljava/lang/Object;)Ljava/lang/Object;
 }
 
-public final class org/partiql/ast/Expr$Agg : org/partiql/ast/Expr {
-	public static final field Companion Lorg/partiql/ast/Expr$Agg$Companion;
-	public final field args Ljava/util/List;
-	public final field function Lorg/partiql/ast/Identifier;
-	public final field setq Lorg/partiql/ast/SetQuantifier;
-	public fun <init> (Lorg/partiql/ast/Identifier;Ljava/util/List;Lorg/partiql/ast/SetQuantifier;)V
-	public fun accept (Lorg/partiql/ast/visitor/AstVisitor;Ljava/lang/Object;)Ljava/lang/Object;
-	public static final fun builder ()Lorg/partiql/ast/builder/ExprAggBuilder;
-	public final fun component1 ()Lorg/partiql/ast/Identifier;
-	public final fun component2 ()Ljava/util/List;
-	public final fun component3 ()Lorg/partiql/ast/SetQuantifier;
-	public final fun copy (Lorg/partiql/ast/Identifier;Ljava/util/List;Lorg/partiql/ast/SetQuantifier;)Lorg/partiql/ast/Expr$Agg;
-	public static synthetic fun copy$default (Lorg/partiql/ast/Expr$Agg;Lorg/partiql/ast/Identifier;Ljava/util/List;Lorg/partiql/ast/SetQuantifier;ILjava/lang/Object;)Lorg/partiql/ast/Expr$Agg;
-	public fun equals (Ljava/lang/Object;)Z
-	public fun getChildren ()Ljava/util/List;
-	public fun hashCode ()I
-	public fun toString ()Ljava/lang/String;
-}
-
-public final class org/partiql/ast/Expr$Agg$Companion {
-	public final fun builder ()Lorg/partiql/ast/builder/ExprAggBuilder;
-}
-
 public final class org/partiql/ast/Expr$BagOp : org/partiql/ast/Expr {
 	public static final field Companion Lorg/partiql/ast/Expr$BagOp$Companion;
 	public final field lhs Lorg/partiql/ast/Expr;
@@ -636,13 +612,15 @@ public final class org/partiql/ast/Expr$Call : org/partiql/ast/Expr {
 	public static final field Companion Lorg/partiql/ast/Expr$Call$Companion;
 	public final field args Ljava/util/List;
 	public final field function Lorg/partiql/ast/Identifier;
-	public fun <init> (Lorg/partiql/ast/Identifier;Ljava/util/List;)V
+	public final field setq Lorg/partiql/ast/SetQuantifier;
+	public fun <init> (Lorg/partiql/ast/Identifier;Ljava/util/List;Lorg/partiql/ast/SetQuantifier;)V
 	public fun accept (Lorg/partiql/ast/visitor/AstVisitor;Ljava/lang/Object;)Ljava/lang/Object;
 	public static final fun builder ()Lorg/partiql/ast/builder/ExprCallBuilder;
 	public final fun component1 ()Lorg/partiql/ast/Identifier;
 	public final fun component2 ()Ljava/util/List;
-	public final fun copy (Lorg/partiql/ast/Identifier;Ljava/util/List;)Lorg/partiql/ast/Expr$Call;
-	public static synthetic fun copy$default (Lorg/partiql/ast/Expr$Call;Lorg/partiql/ast/Identifier;Ljava/util/List;ILjava/lang/Object;)Lorg/partiql/ast/Expr$Call;
+	public final fun component3 ()Lorg/partiql/ast/SetQuantifier;
+	public final fun copy (Lorg/partiql/ast/Identifier;Ljava/util/List;Lorg/partiql/ast/SetQuantifier;)Lorg/partiql/ast/Expr$Call;
+	public static synthetic fun copy$default (Lorg/partiql/ast/Expr$Call;Lorg/partiql/ast/Identifier;Ljava/util/List;Lorg/partiql/ast/SetQuantifier;ILjava/lang/Object;)Lorg/partiql/ast/Expr$Call;
 	public fun equals (Ljava/lang/Object;)Z
 	public fun getChildren ()Ljava/util/List;
 	public fun hashCode ()I
@@ -4028,16 +4006,14 @@ public final class org/partiql/ast/builder/AstBuilder {
 	public static synthetic fun excludeStepStructField$default (Lorg/partiql/ast/builder/AstBuilder;Lorg/partiql/ast/Identifier$Symbol;Lkotlin/jvm/functions/Function1;ILjava/lang/Object;)Lorg/partiql/ast/Exclude$Step$StructField;
 	public final fun excludeStepStructWildcard (Lkotlin/jvm/functions/Function1;)Lorg/partiql/ast/Exclude$Step$StructWildcard;
 	public static synthetic fun excludeStepStructWildcard$default (Lorg/partiql/ast/builder/AstBuilder;Lkotlin/jvm/functions/Function1;ILjava/lang/Object;)Lorg/partiql/ast/Exclude$Step$StructWildcard;
-	public final fun exprAgg (Lorg/partiql/ast/Identifier;Ljava/util/List;Lorg/partiql/ast/SetQuantifier;Lkotlin/jvm/functions/Function1;)Lorg/partiql/ast/Expr$Agg;
-	public static synthetic fun exprAgg$default (Lorg/partiql/ast/builder/AstBuilder;Lorg/partiql/ast/Identifier;Ljava/util/List;Lorg/partiql/ast/SetQuantifier;Lkotlin/jvm/functions/Function1;ILjava/lang/Object;)Lorg/partiql/ast/Expr$Agg;
 	public final fun exprBagOp (Lorg/partiql/ast/SetOp;Lorg/partiql/ast/Expr;Lorg/partiql/ast/Expr;Ljava/lang/Boolean;Lkotlin/jvm/functions/Function1;)Lorg/partiql/ast/Expr$BagOp;
 	public static synthetic fun exprBagOp$default (Lorg/partiql/ast/builder/AstBuilder;Lorg/partiql/ast/SetOp;Lorg/partiql/ast/Expr;Lorg/partiql/ast/Expr;Ljava/lang/Boolean;Lkotlin/jvm/functions/Function1;ILjava/lang/Object;)Lorg/partiql/ast/Expr$BagOp;
 	public final fun exprBetween (Lorg/partiql/ast/Expr;Lorg/partiql/ast/Expr;Lorg/partiql/ast/Expr;Ljava/lang/Boolean;Lkotlin/jvm/functions/Function1;)Lorg/partiql/ast/Expr$Between;
 	public static synthetic fun exprBetween$default (Lorg/partiql/ast/builder/AstBuilder;Lorg/partiql/ast/Expr;Lorg/partiql/ast/Expr;Lorg/partiql/ast/Expr;Ljava/lang/Boolean;Lkotlin/jvm/functions/Function1;ILjava/lang/Object;)Lorg/partiql/ast/Expr$Between;
 	public final fun exprBinary (Lorg/partiql/ast/Expr$Binary$Op;Lorg/partiql/ast/Expr;Lorg/partiql/ast/Expr;Lkotlin/jvm/functions/Function1;)Lorg/partiql/ast/Expr$Binary;
 	public static synthetic fun exprBinary$default (Lorg/partiql/ast/builder/AstBuilder;Lorg/partiql/ast/Expr$Binary$Op;Lorg/partiql/ast/Expr;Lorg/partiql/ast/Expr;Lkotlin/jvm/functions/Function1;ILjava/lang/Object;)Lorg/partiql/ast/Expr$Binary;
-	public final fun exprCall (Lorg/partiql/ast/Identifier;Ljava/util/List;Lkotlin/jvm/functions/Function1;)Lorg/partiql/ast/Expr$Call;
-	public static synthetic fun exprCall$default (Lorg/partiql/ast/builder/AstBuilder;Lorg/partiql/ast/Identifier;Ljava/util/List;Lkotlin/jvm/functions/Function1;ILjava/lang/Object;)Lorg/partiql/ast/Expr$Call;
+	public final fun exprCall (Lorg/partiql/ast/Identifier;Ljava/util/List;Lorg/partiql/ast/SetQuantifier;Lkotlin/jvm/functions/Function1;)Lorg/partiql/ast/Expr$Call;
+	public static synthetic fun exprCall$default (Lorg/partiql/ast/builder/AstBuilder;Lorg/partiql/ast/Identifier;Ljava/util/List;Lorg/partiql/ast/SetQuantifier;Lkotlin/jvm/functions/Function1;ILjava/lang/Object;)Lorg/partiql/ast/Expr$Call;
 	public final fun exprCanCast (Lorg/partiql/ast/Expr;Lorg/partiql/ast/Type;Lkotlin/jvm/functions/Function1;)Lorg/partiql/ast/Expr$CanCast;
 	public static synthetic fun exprCanCast$default (Lorg/partiql/ast/builder/AstBuilder;Lorg/partiql/ast/Expr;Lorg/partiql/ast/Type;Lkotlin/jvm/functions/Function1;ILjava/lang/Object;)Lorg/partiql/ast/Expr$CanCast;
 	public final fun exprCanLosslessCast (Lorg/partiql/ast/Expr;Lorg/partiql/ast/Type;Lkotlin/jvm/functions/Function1;)Lorg/partiql/ast/Expr$CanLosslessCast;
@@ -4497,22 +4473,6 @@ public final class org/partiql/ast/builder/ExcludeStepStructWildcardBuilder {
 	public final fun build ()Lorg/partiql/ast/Exclude$Step$StructWildcard;
 }
 
-public final class org/partiql/ast/builder/ExprAggBuilder {
-	public fun <init> ()V
-	public fun <init> (Lorg/partiql/ast/Identifier;Ljava/util/List;Lorg/partiql/ast/SetQuantifier;)V
-	public synthetic fun <init> (Lorg/partiql/ast/Identifier;Ljava/util/List;Lorg/partiql/ast/SetQuantifier;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
-	public final fun args (Ljava/util/List;)Lorg/partiql/ast/builder/ExprAggBuilder;
-	public final fun build ()Lorg/partiql/ast/Expr$Agg;
-	public final fun function (Lorg/partiql/ast/Identifier;)Lorg/partiql/ast/builder/ExprAggBuilder;
-	public final fun getArgs ()Ljava/util/List;
-	public final fun getFunction ()Lorg/partiql/ast/Identifier;
-	public final fun getSetq ()Lorg/partiql/ast/SetQuantifier;
-	public final fun setArgs (Ljava/util/List;)V
-	public final fun setFunction (Lorg/partiql/ast/Identifier;)V
-	public final fun setSetq (Lorg/partiql/ast/SetQuantifier;)V
-	public final fun setq (Lorg/partiql/ast/SetQuantifier;)Lorg/partiql/ast/builder/ExprAggBuilder;
-}
-
 public final class org/partiql/ast/builder/ExprBagOpBuilder {
 	public fun <init> ()V
 	public fun <init> (Lorg/partiql/ast/SetOp;Lorg/partiql/ast/Expr;Lorg/partiql/ast/Expr;Ljava/lang/Boolean;)V
@@ -4569,15 +4529,18 @@ public final class org/partiql/ast/builder/ExprBinaryBuilder {
 
 public final class org/partiql/ast/builder/ExprCallBuilder {
 	public fun <init> ()V
-	public fun <init> (Lorg/partiql/ast/Identifier;Ljava/util/List;)V
-	public synthetic fun <init> (Lorg/partiql/ast/Identifier;Ljava/util/List;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public fun <init> (Lorg/partiql/ast/Identifier;Ljava/util/List;Lorg/partiql/ast/SetQuantifier;)V
+	public synthetic fun <init> (Lorg/partiql/ast/Identifier;Ljava/util/List;Lorg/partiql/ast/SetQuantifier;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public final fun args (Ljava/util/List;)Lorg/partiql/ast/builder/ExprCallBuilder;
 	public final fun build ()Lorg/partiql/ast/Expr$Call;
 	public final fun function (Lorg/partiql/ast/Identifier;)Lorg/partiql/ast/builder/ExprCallBuilder;
 	public final fun getArgs ()Ljava/util/List;
 	public final fun getFunction ()Lorg/partiql/ast/Identifier;
+	public final fun getSetq ()Lorg/partiql/ast/SetQuantifier;
 	public final fun setArgs (Ljava/util/List;)V
 	public final fun setFunction (Lorg/partiql/ast/Identifier;)V
+	public final fun setSetq (Lorg/partiql/ast/SetQuantifier;)V
+	public final fun setq (Lorg/partiql/ast/SetQuantifier;)Lorg/partiql/ast/builder/ExprCallBuilder;
 }
 
 public final class org/partiql/ast/builder/ExprCanCastBuilder {
@@ -6406,8 +6369,6 @@ public abstract class org/partiql/ast/sql/SqlDialect : org/partiql/ast/visitor/A
 	public fun visitExcludeStepStructField (Lorg/partiql/ast/Exclude$Step$StructField;Lorg/partiql/ast/sql/SqlBlock;)Lorg/partiql/ast/sql/SqlBlock;
 	public synthetic fun visitExcludeStepStructWildcard (Lorg/partiql/ast/Exclude$Step$StructWildcard;Ljava/lang/Object;)Ljava/lang/Object;
 	public fun visitExcludeStepStructWildcard (Lorg/partiql/ast/Exclude$Step$StructWildcard;Lorg/partiql/ast/sql/SqlBlock;)Lorg/partiql/ast/sql/SqlBlock;
-	public synthetic fun visitExprAgg (Lorg/partiql/ast/Expr$Agg;Ljava/lang/Object;)Ljava/lang/Object;
-	public fun visitExprAgg (Lorg/partiql/ast/Expr$Agg;Lorg/partiql/ast/sql/SqlBlock;)Lorg/partiql/ast/sql/SqlBlock;
 	public synthetic fun visitExprBagOp (Lorg/partiql/ast/Expr$BagOp;Ljava/lang/Object;)Ljava/lang/Object;
 	public fun visitExprBagOp (Lorg/partiql/ast/Expr$BagOp;Lorg/partiql/ast/sql/SqlBlock;)Lorg/partiql/ast/sql/SqlBlock;
 	public synthetic fun visitExprBetween (Lorg/partiql/ast/Expr$Between;Ljava/lang/Object;)Ljava/lang/Object;
@@ -6681,8 +6642,6 @@ public abstract class org/partiql/ast/util/AstRewriter : org/partiql/ast/visitor
 	public fun visitExcludeStepStructField (Lorg/partiql/ast/Exclude$Step$StructField;Ljava/lang/Object;)Lorg/partiql/ast/AstNode;
 	public synthetic fun visitExcludeStepStructWildcard (Lorg/partiql/ast/Exclude$Step$StructWildcard;Ljava/lang/Object;)Ljava/lang/Object;
 	public fun visitExcludeStepStructWildcard (Lorg/partiql/ast/Exclude$Step$StructWildcard;Ljava/lang/Object;)Lorg/partiql/ast/AstNode;
-	public synthetic fun visitExprAgg (Lorg/partiql/ast/Expr$Agg;Ljava/lang/Object;)Ljava/lang/Object;
-	public fun visitExprAgg (Lorg/partiql/ast/Expr$Agg;Ljava/lang/Object;)Lorg/partiql/ast/AstNode;
 	public synthetic fun visitExprBagOp (Lorg/partiql/ast/Expr$BagOp;Ljava/lang/Object;)Ljava/lang/Object;
 	public fun visitExprBagOp (Lorg/partiql/ast/Expr$BagOp;Ljava/lang/Object;)Lorg/partiql/ast/AstNode;
 	public synthetic fun visitExprBetween (Lorg/partiql/ast/Expr$Between;Ljava/lang/Object;)Ljava/lang/Object;
@@ -7013,7 +6972,6 @@ public abstract class org/partiql/ast/visitor/AstBaseVisitor : org/partiql/ast/v
 	public fun visitExcludeStepStructField (Lorg/partiql/ast/Exclude$Step$StructField;Ljava/lang/Object;)Ljava/lang/Object;
 	public fun visitExcludeStepStructWildcard (Lorg/partiql/ast/Exclude$Step$StructWildcard;Ljava/lang/Object;)Ljava/lang/Object;
 	public fun visitExpr (Lorg/partiql/ast/Expr;Ljava/lang/Object;)Ljava/lang/Object;
-	public fun visitExprAgg (Lorg/partiql/ast/Expr$Agg;Ljava/lang/Object;)Ljava/lang/Object;
 	public fun visitExprBagOp (Lorg/partiql/ast/Expr$BagOp;Ljava/lang/Object;)Ljava/lang/Object;
 	public fun visitExprBetween (Lorg/partiql/ast/Expr$Between;Ljava/lang/Object;)Ljava/lang/Object;
 	public fun visitExprBinary (Lorg/partiql/ast/Expr$Binary;Ljava/lang/Object;)Ljava/lang/Object;
@@ -7207,7 +7165,6 @@ public abstract interface class org/partiql/ast/visitor/AstVisitor {
 	public abstract fun visitExcludeStepStructField (Lorg/partiql/ast/Exclude$Step$StructField;Ljava/lang/Object;)Ljava/lang/Object;
 	public abstract fun visitExcludeStepStructWildcard (Lorg/partiql/ast/Exclude$Step$StructWildcard;Ljava/lang/Object;)Ljava/lang/Object;
 	public abstract fun visitExpr (Lorg/partiql/ast/Expr;Ljava/lang/Object;)Ljava/lang/Object;
-	public abstract fun visitExprAgg (Lorg/partiql/ast/Expr$Agg;Ljava/lang/Object;)Ljava/lang/Object;
 	public abstract fun visitExprBagOp (Lorg/partiql/ast/Expr$BagOp;Ljava/lang/Object;)Ljava/lang/Object;
 	public abstract fun visitExprBetween (Lorg/partiql/ast/Expr$Between;Ljava/lang/Object;)Ljava/lang/Object;
 	public abstract fun visitExprBinary (Lorg/partiql/ast/Expr$Binary;Ljava/lang/Object;)Ljava/lang/Object;
diff --git a/partiql-ast/src/main/kotlin/org/partiql/ast/helpers/ToLegacyAst.kt b/partiql-ast/src/main/kotlin/org/partiql/ast/helpers/ToLegacyAst.kt
index d2a07a7982..fd7fdb2a90 100644
--- a/partiql-ast/src/main/kotlin/org/partiql/ast/helpers/ToLegacyAst.kt
+++ b/partiql-ast/src/main/kotlin/org/partiql/ast/helpers/ToLegacyAst.kt
@@ -309,26 +309,29 @@ private class AstTranslator(val metas: Map<String, MetaContainer>) : AstBaseVisi
         }
         val funcName = (node.function as Identifier.Symbol).symbol.lowercase()
         val args = node.args.translate<PartiqlAst.Expr>(ctx)
-        call(funcName, args, metas)
+        when (funcName.isAggregateCall() || node.setq != null) { // Use existing assumption that function call with set quantifier is an aggregation function
+            true -> {
+                val setq = node.setq?.toLegacySetQuantifier() ?: all()
+                // COUNT(*) is represented as COUNT() in default AST
+                // Legacy AST translates COUNT(*) to COUNT(1)
+                if (funcName == "count" && args.isEmpty()) {
+                    return callAgg(setq, "count", lit(ionInt(1)), metas)
+                }
+                // Default Case
+                if (node.args.size != 1) {
+                    error("Cannot translate `call_agg` with more than one argument")
+                }
+                val arg = visitExpr(node.args[0], ctx)
+                callAgg(setq, funcName, arg, metas)
+            }
+            false -> call(funcName, args, metas)
+        }
     }
 
-    override fun visitExprAgg(node: Expr.Agg, ctx: Ctx) = translate(node) { metas ->
-        val setq = node.setq?.toLegacySetQuantifier() ?: all()
-        // Legacy AST translates COUNT(*) to COUNT(1)
-        if (node.function is Identifier.Symbol && (node.function as Identifier.Symbol).symbol == "COUNT_STAR") {
-            return callAgg(setq, "count", lit(ionInt(1)), metas)
-        }
-        // Default Case
-        if (node.args.size != 1) {
-            error("Legacy `call_agg` must have exactly one argument")
-        }
-        if (node.function is Identifier.Qualified) {
-            error("Qualified identifiers are not allowed in legacy AST `call_agg` function identifiers")
-        }
-        // Legacy parser/ast always inserts ALL quantifier
-        val funcName = (node.function as Identifier.Symbol).symbol.lowercase()
-        val arg = visitExpr(node.args[0], ctx)
-        callAgg(setq, funcName, arg, metas)
+    private fun String.isAggregateCall(): Boolean {
+        // like PartiQLPigVisitor, keep legacy behavior the same as before
+        // since it is legacy, hard-coded aggregation logic
+        return listOf("count", "avg", "sum", "min", "max", "any", "some", "every").contains(this)
     }
 
     override fun visitExprUnary(node: Expr.Unary, ctx: Ctx) = translate(node) { metas ->
diff --git a/partiql-ast/src/main/kotlin/org/partiql/ast/sql/SqlDialect.kt b/partiql-ast/src/main/kotlin/org/partiql/ast/sql/SqlDialect.kt
index 6a589a0556..97a863566e 100644
--- a/partiql-ast/src/main/kotlin/org/partiql/ast/sql/SqlDialect.kt
+++ b/partiql-ast/src/main/kotlin/org/partiql/ast/sql/SqlDialect.kt
@@ -304,17 +304,10 @@ public abstract class SqlDialect : AstBaseVisitor<SqlBlock, SqlBlock>() {
     override fun visitExprPathStepUnpivot(node: Expr.Path.Step.Unpivot, head: SqlBlock): SqlBlock = head concat r(".*")
 
     override fun visitExprCall(node: Expr.Call, head: SqlBlock): SqlBlock {
-        var h = head
-        h = visitIdentifier(node.function, h)
-        h = h concat list { node.args }
-        return h
-    }
-
-    override fun visitExprAgg(node: Expr.Agg, head: SqlBlock): SqlBlock {
         var h = head
         val f = node.function
-        // Special case
-        if (f is Identifier.Symbol && f.symbol == "COUNT_STAR") {
+        // Special case -- COUNT() maps to COUNT(*)
+        if (f is Identifier.Symbol && f.symbol == "COUNT" && node.args.isEmpty()) {
             return h concat r("COUNT(*)")
         }
         val start = if (node.setq != null) "(${node.setq.name} " else "("
diff --git a/partiql-ast/src/main/kotlin/org/partiql/ast/sql/internal/InternalSqlDialect.kt b/partiql-ast/src/main/kotlin/org/partiql/ast/sql/internal/InternalSqlDialect.kt
index b01b56e680..6c93aa009b 100644
--- a/partiql-ast/src/main/kotlin/org/partiql/ast/sql/internal/InternalSqlDialect.kt
+++ b/partiql-ast/src/main/kotlin/org/partiql/ast/sql/internal/InternalSqlDialect.kt
@@ -330,20 +330,13 @@ internal abstract class InternalSqlDialect : AstBaseVisitor<InternalSqlBlock, In
     override fun visitExprPathStepUnpivot(node: Expr.Path.Step.Unpivot, tail: InternalSqlBlock): InternalSqlBlock = tail concat ".*"
 
     override fun visitExprCall(node: Expr.Call, tail: InternalSqlBlock): InternalSqlBlock {
-        var t = tail
-        t = visitIdentifier(node.function, t)
-        t = t concat list { node.args }
-        return t
-    }
-
-    override fun visitExprAgg(node: Expr.Agg, tail: InternalSqlBlock): InternalSqlBlock {
         var t = tail
         val f = node.function
-        // Special case
-        if (f is Identifier.Symbol && f.symbol == "COUNT_STAR") {
+        // Special case -- COUNT() maps to COUNT(*)
+        if (f is Identifier.Symbol && f.symbol == "COUNT" && node.args.isEmpty()) {
             return t concat "COUNT(*)"
         }
-        val start = if (node.setq != null) "(${node.setq!!.name} " else "("
+        val start = if (node.setq != null) "(${node.setq.name} " else "("
         t = visitIdentifier(f, t)
         t = t concat list(start) { node.args }
         return t
diff --git a/partiql-ast/src/main/resources/partiql_ast.ion b/partiql-ast/src/main/resources/partiql_ast.ion
index 5c6aea16b6..a7b32727fd 100644
--- a/partiql-ast/src/main/resources/partiql_ast.ion
+++ b/partiql-ast/src/main/resources/partiql_ast.ion
@@ -342,17 +342,11 @@ expr::[
     ],
   },
 
-  // Scalar Function Call
+  // Function Call (both scalar + aggregate)
   call::{
     function: identifier,
     args:     list::[expr],
-  },
-
-  // Aggregate Function Call
-  agg::{
-    function: identifier,
-    args:     list::[expr],
-    setq:     optional::set_quantifier,
+    setq:     optional::set_quantifier
   },
 
   // Parameter `?`
diff --git a/partiql-ast/src/test/kotlin/org/partiql/ast/helpers/ToLegacyAstTest.kt b/partiql-ast/src/test/kotlin/org/partiql/ast/helpers/ToLegacyAstTest.kt
index 11d1f97c70..440b9911d4 100644
--- a/partiql-ast/src/test/kotlin/org/partiql/ast/helpers/ToLegacyAstTest.kt
+++ b/partiql-ast/src/test/kotlin/org/partiql/ast/helpers/ToLegacyAstTest.kt
@@ -254,29 +254,30 @@ class ToLegacyAstTest {
                     args += NULL
                 }
             },
-            expect("(call_agg (all) 'a' (lit null))") {
-                exprAgg {
+            expect("(call 'a' (lit null))") {
+                exprCall {
                     function = id("a")
                     args += NULL
                 }
             },
             expect("(call_agg (all) 'a' (lit null))") {
-                exprAgg {
+                exprCall {
                     setq = SetQuantifier.ALL
                     function = id("a")
                     args += NULL
                 }
             },
             expect("(call_agg (distinct) 'a' (lit null))") {
-                exprAgg {
+                exprCall {
                     setq = SetQuantifier.DISTINCT
                     function = id("a")
                     args += NULL
                 }
             },
             fail("Cannot translate `call_agg` with more than one argument") {
-                exprAgg {
+                exprCall {
                     function = id("a")
+                    setq = SetQuantifier.DISTINCT // define a setq for legacy ast test to force `call_agg` logic
                     args += listOf(NULL, NULL)
                 }
             },
diff --git a/partiql-ast/src/test/kotlin/org/partiql/ast/sql/SqlDialectTest.kt b/partiql-ast/src/test/kotlin/org/partiql/ast/sql/SqlDialectTest.kt
index 039fbd4112..e93e1294f8 100644
--- a/partiql-ast/src/test/kotlin/org/partiql/ast/sql/SqlDialectTest.kt
+++ b/partiql-ast/src/test/kotlin/org/partiql/ast/sql/SqlDialectTest.kt
@@ -599,34 +599,34 @@ class SqlDialectTest {
         @JvmStatic
         fun exprAggCases() = listOf(
             expect("FOO(x)") {
-                exprAgg {
+                exprCall {
                     function = id("FOO")
                     args += exprVar(id("x"), Expr.Var.Scope.DEFAULT)
                 }
             },
             expect("FOO(ALL x)") {
-                exprAgg {
+                exprCall {
                     function = id("FOO")
                     setq = SetQuantifier.ALL
                     args += exprVar(id("x"), Expr.Var.Scope.DEFAULT)
                 }
             },
             expect("FOO(DISTINCT x)") {
-                exprAgg {
+                exprCall {
                     function = id("FOO")
                     setq = SetQuantifier.DISTINCT
                     args += exprVar(id("x"), Expr.Var.Scope.DEFAULT)
                 }
             },
             expect("FOO(x, y)") {
-                exprAgg {
+                exprCall {
                     function = id("FOO")
                     args += exprVar(id("x"), Expr.Var.Scope.DEFAULT)
                     args += exprVar(id("y"), Expr.Var.Scope.DEFAULT)
                 }
             },
             expect("FOO(ALL x, y)") {
-                exprAgg {
+                exprCall {
                     function = id("FOO")
                     setq = SetQuantifier.ALL
                     args += exprVar(id("x"), Expr.Var.Scope.DEFAULT)
@@ -634,7 +634,7 @@ class SqlDialectTest {
                 }
             },
             expect("FOO(DISTINCT x, y)") {
-                exprAgg {
+                exprCall {
                     function = id("FOO")
                     setq = SetQuantifier.DISTINCT
                     args += exprVar(id("x"), Expr.Var.Scope.DEFAULT)
@@ -642,8 +642,8 @@ class SqlDialectTest {
                 }
             },
             expect("COUNT(*)") {
-                exprAgg {
-                    function = id("COUNT_STAR")
+                exprCall {
+                    function = id("COUNT") // AST representation for COUNT w/ no args maps to COUNT(*)
                 }
             }
         )
diff --git a/partiql-lang/src/main/kotlin/org/partiql/lang/syntax/impl/PartiQLPigVisitor.kt b/partiql-lang/src/main/kotlin/org/partiql/lang/syntax/impl/PartiQLPigVisitor.kt
index 31b588c079..46c2ebe39f 100644
--- a/partiql-lang/src/main/kotlin/org/partiql/lang/syntax/impl/PartiQLPigVisitor.kt
+++ b/partiql-lang/src/main/kotlin/org/partiql/lang/syntax/impl/PartiQLPigVisitor.kt
@@ -1325,16 +1325,48 @@ internal class PartiQLPigVisitor(
         canLosslessCast(expr, type, metas)
     }
 
-    override fun visitFunctionCall(ctx: PartiQLParser.FunctionCallContext) = PartiqlAst.build {
+    override fun visitFunctionCall(ctx: PartiQLParser.FunctionCallContext): PartiqlAst.Expr = PartiqlAst.build {
         val nameCtx = ctx.qualifiedName()
         val name = if (nameCtx.qualifier.isNotEmpty()) {
             error("Legacy AST does not support qualified function names")
         } else {
             nameCtx.name.getString().lowercase()
         }
-        val args = ctx.expr().map { visitExpr(it) }
-        val metas = ctx.start.getSourceMetaContainer()
-        call(name, args = args, metas = metas)
+        // COUNT(*) turns into COUNT(1) in legacy PIG AST
+        if (ctx.ASTERISK() != null) {
+            if (name == "count") {
+                return@build callAgg(
+                    all(),
+                    name,
+                    lit(ionInt(1)),
+                    nameCtx.name.getSourceMetaContainer() + metaContainerOf(IsCountStarMeta.instance)
+                )
+            } else {
+                // Do not permit wildcard for other functions; matches existing behavior
+                error("Given wildcard as argument for non-COUNT function")
+            }
+        }
+        if (!name.isAggregateCall()) {
+            // Scalar fn call
+            val args = ctx.expr().map { visitExpr(it) }
+            val metas = ctx.start.getSourceMetaContainer()
+            return@build call(name, args = args, metas = metas)
+        }
+        // Aggregate fn call
+        val strategy = getStrategy(ctx.setQuantifierStrategy(), default = all())
+        val args = ctx.expr()
+        if (args.size != 1) {
+            error("expect only one argument to aggregate function call")
+        }
+        val arg = visitExpr(args.first())
+        val metas = nameCtx.name.getSourceMetaContainer()
+        return@build callAgg(strategy, name, arg, metas)
+    }
+
+    private fun String.isAggregateCall(): Boolean {
+        // keep legacy PIG parser behavior + PIG AST the same as before
+        // since it is legacy, we will keep this hard-coded aggregation logic
+        return listOf("count", "avg", "sum", "min", "max", "any", "some", "every").contains(this)
     }
 
     override fun visitDateFunction(ctx: PartiQLParser.DateFunctionContext) = PartiqlAst.build {
@@ -1366,15 +1398,6 @@ internal class PartiQLPigVisitor(
         call(ctx.OVERLAY().text.lowercase(), args, metas)
     }
 
-    override fun visitCountAll(ctx: PartiQLParser.CountAllContext) = PartiqlAst.build {
-        callAgg(
-            all(),
-            ctx.func.text.lowercase(),
-            lit(ionInt(1)),
-            ctx.COUNT().getSourceMetaContainer() + metaContainerOf(IsCountStarMeta.instance)
-        )
-    }
-
     override fun visitExtract(ctx: PartiQLParser.ExtractContext) = PartiqlAst.build {
         if (DateTimePart.safeValueOf(ctx.IDENTIFIER().text) == null) {
             throw ctx.IDENTIFIER()
@@ -1432,13 +1455,6 @@ internal class PartiQLPigVisitor(
         call(ctx.func.text.lowercase(), args, metas)
     }
 
-    override fun visitAggregateBase(ctx: PartiQLParser.AggregateBaseContext) = PartiqlAst.build {
-        val strategy = getStrategy(ctx.setQuantifierStrategy(), default = all())
-        val arg = visitExpr(ctx.expr())
-        val metas = ctx.func.getSourceMetaContainer()
-        callAgg(strategy, ctx.func.text.lowercase(), arg, metas)
-    }
-
     /**
      *
      * Window Functions
diff --git a/partiql-parser/src/main/antlr/PartiQL.g4 b/partiql-parser/src/main/antlr/PartiQL.g4
index 0267c8983b..04af26461e 100644
--- a/partiql-parser/src/main/antlr/PartiQL.g4
+++ b/partiql-parser/src/main/antlr/PartiQL.g4
@@ -653,7 +653,6 @@ exprPrimary
     | extract                    # ExprPrimaryBase
     | coalesce                   # ExprPrimaryBase
     | dateFunction               # ExprPrimaryBase
-    | aggregate                  # ExprPrimaryBase
     | trimFunction               # ExprPrimaryBase
     | nullIf                     # ExprPrimaryBase
     | functionCall               # ExprPrimaryBase
@@ -726,11 +725,6 @@ overlay
     | OVERLAY PAREN_LEFT expr PLACING expr FROM expr (FOR expr)? PAREN_RIGHT
     ;
 
-aggregate
-    : func=COUNT PAREN_LEFT ASTERISK PAREN_RIGHT                                        # CountAll
-    | func=(COUNT|MAX|MIN|SUM|AVG|EVERY|ANY|SOME) PAREN_LEFT setQuantifierStrategy? expr PAREN_RIGHT   # AggregateBase
-    ;
-
 // TODO: Remove from experimental once https://github.com/partiql/partiql-docs/issues/31 is resolved and a RFC is approved
 /**
 *
@@ -763,7 +757,8 @@ dateFunction
 
 // SQL-99 10.4 — <routine invocation> ::= <routine name> <SQL argument list>
 functionCall
-    : qualifiedName PAREN_LEFT ( expr ( COMMA expr )* )? PAREN_RIGHT
+    : qualifiedName PAREN_LEFT ASTERISK PAREN_RIGHT
+    | qualifiedName PAREN_LEFT ( setQuantifierStrategy? expr ( COMMA expr )* )? PAREN_RIGHT
     ;
 
 pathStep
@@ -831,6 +826,8 @@ nonReserved
     /* PartiQL */
     | EXCLUDED | EXISTS
     | SIZE
+    /* Other words not in above */
+    | ANY | SOME
     ;
 
 /**
diff --git a/partiql-parser/src/main/kotlin/org/partiql/parser/internal/PartiQLParserDefault.kt b/partiql-parser/src/main/kotlin/org/partiql/parser/internal/PartiQLParserDefault.kt
index 27a1b39da4..8dc143a3b2 100644
--- a/partiql-parser/src/main/kotlin/org/partiql/parser/internal/PartiQLParserDefault.kt
+++ b/partiql-parser/src/main/kotlin/org/partiql/parser/internal/PartiQLParserDefault.kt
@@ -68,7 +68,6 @@ import org.partiql.ast.excludeStepCollIndex
 import org.partiql.ast.excludeStepCollWildcard
 import org.partiql.ast.excludeStepStructField
 import org.partiql.ast.excludeStepStructWildcard
-import org.partiql.ast.exprAgg
 import org.partiql.ast.exprBagOp
 import org.partiql.ast.exprBetween
 import org.partiql.ast.exprBinary
@@ -1865,11 +1864,11 @@ internal class PartiQLParserDefault : PartiQLParser {
                             val path = ctx.qualifiedName().qualifier.map { visitSymbolPrimitive(it) }
                             val name = identifierSymbol("char_length", Identifier.CaseSensitivity.INSENSITIVE)
                             if (path.isEmpty()) {
-                                exprCall(name, args)
+                                exprCall(name, args, setq = null) // setq = null for scalar fn
                             } else {
                                 val root = path.first()
                                 val steps = path.drop(1) + listOf(name)
-                                exprCall(identifierQualified(root, steps), args)
+                                exprCall(identifierQualified(root, steps), args, setq = null)
                             }
                         }
                         else -> visitNonReservedFunctionCall(ctx, args)
@@ -1880,7 +1879,7 @@ internal class PartiQLParserDefault : PartiQLParser {
         }
         private fun visitNonReservedFunctionCall(ctx: GeneratedParser.FunctionCallContext, args: List<Expr>): Expr.Call {
             val function = visitQualifiedName(ctx.qualifiedName())
-            return exprCall(function, args)
+            return exprCall(function, args, convertSetQuantifier(ctx.setQuantifierStrategy()))
         }
 
         /**
@@ -1912,7 +1911,7 @@ internal class PartiQLParserDefault : PartiQLParser {
                 // normal form
                 val function = "SUBSTRING".toIdentifier()
                 val args = visitOrEmpty<Expr>(ctx.expr())
-                exprCall(function, args)
+                exprCall(function, args, setq = null) // setq = null for scalar fn
             } else {
                 // special form
                 val value = visitExpr(ctx.expr(0))
@@ -1930,7 +1929,7 @@ internal class PartiQLParserDefault : PartiQLParser {
                 // normal form
                 val function = "POSITION".toIdentifier()
                 val args = visitOrEmpty<Expr>(ctx.expr())
-                exprCall(function, args)
+                exprCall(function, args, setq = null) // setq = null for scalar fn
             } else {
                 // special form
                 val lhs = visitExpr(ctx.expr(0))
@@ -1965,14 +1964,6 @@ internal class PartiQLParserDefault : PartiQLParser {
             }
         }
 
-        /**
-         * COUNT(*)
-         */
-        override fun visitCountAll(ctx: GeneratedParser.CountAllContext) = translate(ctx) {
-            val function = "COUNT_STAR".toIdentifier()
-            exprAgg(function, emptyList(), SetQuantifier.ALL)
-        }
-
         override fun visitExtract(ctx: GeneratedParser.ExtractContext) = translate(ctx) {
             val field = try {
                 DatetimeField.valueOf(ctx.IDENTIFIER().text.uppercase())
@@ -1999,13 +1990,6 @@ internal class PartiQLParserDefault : PartiQLParser {
             exprTrim(value, chars, spec)
         }
 
-        override fun visitAggregateBase(ctx: GeneratedParser.AggregateBaseContext) = translate(ctx) {
-            val function = ctx.func.text.toIdentifier()
-            val args = listOf(visitExpr(ctx.expr()))
-            val setq = convertSetQuantifier(ctx.setQuantifierStrategy())
-            exprAgg(function, args, setq)
-        }
-
         /**
          * Window Functions
          */
diff --git a/partiql-parser/src/test/kotlin/org/partiql/parser/internal/PartiQLParserFunctionCallTests.kt b/partiql-parser/src/test/kotlin/org/partiql/parser/internal/PartiQLParserFunctionCallTests.kt
index a562805895..a35372845c 100644
--- a/partiql-parser/src/test/kotlin/org/partiql/parser/internal/PartiQLParserFunctionCallTests.kt
+++ b/partiql-parser/src/test/kotlin/org/partiql/parser/internal/PartiQLParserFunctionCallTests.kt
@@ -22,7 +22,8 @@ class PartiQLParserFunctionCallTests {
         query {
             exprCall(
                 function = identifierSymbol("foo", Identifier.CaseSensitivity.INSENSITIVE),
-                args = emptyList()
+                args = emptyList(),
+                setq = null
             )
         }
     )
@@ -33,7 +34,8 @@ class PartiQLParserFunctionCallTests {
         query {
             exprCall(
                 function = identifierSymbol("foo", Identifier.CaseSensitivity.SENSITIVE),
-                args = emptyList()
+                args = emptyList(),
+                setq = null
             )
         }
     )
@@ -44,7 +46,8 @@ class PartiQLParserFunctionCallTests {
         query {
             exprCall(
                 function = identifierSymbol("upper", Identifier.CaseSensitivity.INSENSITIVE),
-                args = emptyList()
+                args = emptyList(),
+                setq = null
             )
         }
     )
@@ -55,7 +58,8 @@ class PartiQLParserFunctionCallTests {
         query {
             exprCall(
                 function = identifierSymbol("upper", Identifier.CaseSensitivity.SENSITIVE),
-                args = emptyList()
+                args = emptyList(),
+                setq = null
             )
         }
     )
@@ -72,7 +76,8 @@ class PartiQLParserFunctionCallTests {
                         identifierSymbol("foo", Identifier.CaseSensitivity.INSENSITIVE),
                     )
                 ),
-                args = emptyList()
+                args = emptyList(),
+                setq = null
             )
         }
     )
@@ -89,7 +94,8 @@ class PartiQLParserFunctionCallTests {
                         identifierSymbol("foo", Identifier.CaseSensitivity.SENSITIVE),
                     )
                 ),
-                args = emptyList()
+                args = emptyList(),
+                setq = null
             )
         }
     )
@@ -106,7 +112,8 @@ class PartiQLParserFunctionCallTests {
                         identifierSymbol("upper", Identifier.CaseSensitivity.INSENSITIVE),
                     )
                 ),
-                args = emptyList()
+                args = emptyList(),
+                setq = null
             )
         }
     )
@@ -123,7 +130,8 @@ class PartiQLParserFunctionCallTests {
                         identifierSymbol("upper", Identifier.CaseSensitivity.SENSITIVE),
                     )
                 ),
-                args = emptyList()
+                args = emptyList(),
+                setq = null
             )
         }
     )
diff --git a/partiql-planner/src/main/kotlin/org/partiql/planner/internal/Env.kt b/partiql-planner/src/main/kotlin/org/partiql/planner/internal/Env.kt
index 664b321122..478ca2f3a5 100644
--- a/partiql-planner/src/main/kotlin/org/partiql/planner/internal/Env.kt
+++ b/partiql-planner/src/main/kotlin/org/partiql/planner/internal/Env.kt
@@ -34,6 +34,8 @@ import org.partiql.value.PartiQLValueType
  *
  * See TypeEnv for the variables type environment.
  *
+ * TODO: function resolution between scalar functions and aggregations.
+ *
  * @property session
  */
 internal class Env(private val session: PartiQLPlanner.Session) {
diff --git a/partiql-planner/src/main/kotlin/org/partiql/planner/internal/PathResolverAgg.kt b/partiql-planner/src/main/kotlin/org/partiql/planner/internal/PathResolverAgg.kt
index 7a19e15ede..c976626784 100644
--- a/partiql-planner/src/main/kotlin/org/partiql/planner/internal/PathResolverAgg.kt
+++ b/partiql-planner/src/main/kotlin/org/partiql/planner/internal/PathResolverAgg.kt
@@ -8,19 +8,6 @@ import org.partiql.spi.connector.ConnectorHandle
 import org.partiql.spi.connector.ConnectorMetadata
 import org.partiql.spi.fn.FnExperimental
 
-/**
- * Today, all aggregations are hard-coded into the grammar. We cannot implement user-defined aggregations until
- * the grammar and AST are updated appropriately. We should not have an aggregation node in the AST, just a call node.
- * During planning, we would then check if a call is an aggregation and translate the AST to the appropriate algebra.
- *
- * PartiQL.g4
- *
- * aggregate
- *     : func=COUNT PAREN_LEFT ASTERISK PAREN_RIGHT
- *     | func=(COUNT|MAX|MIN|SUM|AVG|EVERY|ANY|SOME) PAREN_LEFT setQuantifierStrategy? expr PAREN_RIGHT
- *     ;
- *
- */
 @OptIn(FnExperimental::class)
 internal class PathResolverAgg(
     catalog: ConnectorMetadata,
diff --git a/partiql-planner/src/main/kotlin/org/partiql/planner/internal/transforms/NormalizeSelect.kt b/partiql-planner/src/main/kotlin/org/partiql/planner/internal/transforms/NormalizeSelect.kt
index 0c4e1f068c..cd2649dd64 100644
--- a/partiql-planner/src/main/kotlin/org/partiql/planner/internal/transforms/NormalizeSelect.kt
+++ b/partiql-planner/src/main/kotlin/org/partiql/planner/internal/transforms/NormalizeSelect.kt
@@ -216,7 +216,8 @@ internal object NormalizeSelect {
             return selectValue(
                 constructor = exprCall(
                     function = identifierSymbol("TUPLEUNION", Identifier.CaseSensitivity.SENSITIVE),
-                    args = tupleUnionArgs
+                    args = tupleUnionArgs,
+                    setq = null // setq = null for scalar fn
                 ),
                 setq = select.setq
             )
@@ -256,7 +257,8 @@ internal object NormalizeSelect {
                 setq = node.setq,
                 constructor = exprCall(
                     function = identifierSymbol("TUPLEUNION", Identifier.CaseSensitivity.SENSITIVE),
-                    args = tupleUnionArgs
+                    args = tupleUnionArgs,
+                    setq = null // setq = null for scalar fn
                 )
             )
         }
diff --git a/partiql-planner/src/main/kotlin/org/partiql/planner/internal/transforms/RelConverter.kt b/partiql-planner/src/main/kotlin/org/partiql/planner/internal/transforms/RelConverter.kt
index 21259c3bed..f45fef89ca 100644
--- a/partiql-planner/src/main/kotlin/org/partiql/planner/internal/transforms/RelConverter.kt
+++ b/partiql-planner/src/main/kotlin/org/partiql/planner/internal/transforms/RelConverter.kt
@@ -28,6 +28,7 @@ import org.partiql.ast.SetOp
 import org.partiql.ast.SetQuantifier
 import org.partiql.ast.Sort
 import org.partiql.ast.builder.ast
+import org.partiql.ast.exprLit
 import org.partiql.ast.exprVar
 import org.partiql.ast.helpers.toBinder
 import org.partiql.ast.identifierSymbol
@@ -71,6 +72,7 @@ import org.partiql.planner.internal.ir.rexOpVarLocal
 import org.partiql.types.StaticType
 import org.partiql.value.PartiQLValueExperimental
 import org.partiql.value.boolValue
+import org.partiql.value.int32Value
 import org.partiql.value.stringValue
 import org.partiql.planner.internal.ir.Identifier as InternalId
 
@@ -367,12 +369,20 @@ internal object RelConverter {
                     is InternalId.Qualified -> error("Qualified aggregation calls are not supported.")
                     is InternalId.Symbol -> id.symbol.lowercase()
                 }
-                val setq = when (expr.setq) {
-                    null -> Rel.Op.Aggregate.SetQuantifier.ALL
-                    SetQuantifier.ALL -> Rel.Op.Aggregate.SetQuantifier.ALL
-                    SetQuantifier.DISTINCT -> Rel.Op.Aggregate.SetQuantifier.DISTINCT
+                if (name == "count" && expr.args.isEmpty()) {
+                    relOpAggregateCallUnresolved(
+                        name,
+                        Rel.Op.Aggregate.SetQuantifier.ALL,
+                        args = listOf(exprLit(int32Value(1)).toRex(env))
+                    )
+                } else {
+                    val setq = when (expr.setq) {
+                        null -> Rel.Op.Aggregate.SetQuantifier.ALL
+                        SetQuantifier.ALL -> Rel.Op.Aggregate.SetQuantifier.ALL
+                        SetQuantifier.DISTINCT -> Rel.Op.Aggregate.SetQuantifier.DISTINCT
+                    }
+                    relOpAggregateCallUnresolved(name, setq, args)
                 }
-                relOpAggregateCallUnresolved(name, setq, args)
             }.toMutableList()
 
             // Add GROUP_AS aggregation
@@ -584,12 +594,12 @@ internal object RelConverter {
     private object AggregationTransform : AstRewriter<AggregationTransform.Context>() {
 
         private data class Context(
-            val aggregations: MutableList<Expr.Agg>,
+            val aggregations: MutableList<Expr.Call>,
             val keys: List<GroupBy.Key>
         )
 
-        fun apply(node: Expr.SFW): Pair<Expr.SFW, List<Expr.Agg>> {
-            val aggs = mutableListOf<Expr.Agg>()
+        fun apply(node: Expr.SFW): Pair<Expr.SFW, List<Expr.Call>> {
+            val aggs = mutableListOf<Expr.Call>()
             val keys = node.groupBy?.keys ?: emptyList()
             val context = Context(aggs, keys)
             val select = super.visitExprSFW(node, context) as Expr.SFW
@@ -607,13 +617,32 @@ internal object RelConverter {
         // only rewrite top-level SFW
         override fun visitExprSFW(node: Expr.SFW, ctx: Context): AstNode = node
 
-        override fun visitExprAgg(node: Expr.Agg, ctx: Context) = ast {
-            val id = identifierSymbol {
-                symbol = syntheticAgg(ctx.aggregations.size)
-                caseSensitivity = org.partiql.ast.Identifier.CaseSensitivity.INSENSITIVE
+        override fun visitExprCall(node: Expr.Call, ctx: Context) = ast {
+            // TODO replace w/ proper function resolution to determine whether a function call is a scalar or aggregate.
+            //  may require further modification of SPI interfaces to support
+            when (node.function.isAggregateCall()) {
+                true -> {
+                    val id = identifierSymbol {
+                        symbol = syntheticAgg(ctx.aggregations.size)
+                        caseSensitivity = org.partiql.ast.Identifier.CaseSensitivity.INSENSITIVE
+                    }
+                    ctx.aggregations += node
+                    exprVar(id, Expr.Var.Scope.DEFAULT)
+                }
+                else -> node
+            }
+        }
+
+        private fun String.isAggregateCall(): Boolean {
+            // currently hard-coded
+            return listOf("count", "avg", "sum", "min", "max", "any", "some", "every").contains(this)
+        }
+
+        private fun Identifier.isAggregateCall(): Boolean {
+            return when (this) {
+                is Identifier.Symbol -> this.symbol.lowercase().isAggregateCall()
+                is Identifier.Qualified -> this.steps.last().symbol.lowercase().isAggregateCall()
             }
-            ctx.aggregations += node
-            exprVar(id, Expr.Var.Scope.DEFAULT)
         }
     }
 
diff --git a/partiql-spi/api/partiql-spi.api b/partiql-spi/api/partiql-spi.api
index 415526a69c..a5208ea8da 100644
--- a/partiql-spi/api/partiql-spi.api
+++ b/partiql-spi/api/partiql-spi.api
@@ -265,14 +265,8 @@ public final class org/partiql/spi/connector/sql/builtins/Agg_AVG__INT__INT : or
 	public fun getSignature ()Lorg/partiql/spi/fn/AggSignature;
 }
 
-public final class org/partiql/spi/connector/sql/builtins/Agg_COUNT_STAR____INT32 : org/partiql/spi/fn/Agg {
-	public static final field INSTANCE Lorg/partiql/spi/connector/sql/builtins/Agg_COUNT_STAR____INT32;
-	public fun accumulator ()Lorg/partiql/spi/fn/Agg$Accumulator;
-	public fun getSignature ()Lorg/partiql/spi/fn/AggSignature;
-}
-
-public final class org/partiql/spi/connector/sql/builtins/Agg_COUNT__ANY__INT32 : org/partiql/spi/fn/Agg {
-	public static final field INSTANCE Lorg/partiql/spi/connector/sql/builtins/Agg_COUNT__ANY__INT32;
+public final class org/partiql/spi/connector/sql/builtins/Agg_COUNT__ANY__INT64 : org/partiql/spi/fn/Agg {
+	public static final field INSTANCE Lorg/partiql/spi/connector/sql/builtins/Agg_COUNT__ANY__INT64;
 	public fun accumulator ()Lorg/partiql/spi/fn/Agg$Accumulator;
 	public fun getSignature ()Lorg/partiql/spi/fn/AggSignature;
 }
diff --git a/partiql-spi/src/main/kotlin/org/partiql/spi/connector/sql/SqlBuiltins.kt b/partiql-spi/src/main/kotlin/org/partiql/spi/connector/sql/SqlBuiltins.kt
index 5df65ed9e6..b3e305b930 100644
--- a/partiql-spi/src/main/kotlin/org/partiql/spi/connector/sql/SqlBuiltins.kt
+++ b/partiql-spi/src/main/kotlin/org/partiql/spi/connector/sql/SqlBuiltins.kt
@@ -446,8 +446,7 @@ internal object SqlBuiltins {
         Agg_AVG__FLOAT32__FLOAT32,
         Agg_AVG__FLOAT64__FLOAT64,
         Agg_AVG__ANY__ANY,
-        Agg_COUNT__ANY__INT32,
-        Agg_COUNT_STAR____INT32,
+        Agg_COUNT__ANY__INT64,
         Agg_EVERY__BOOL__BOOL,
         Agg_EVERY__ANY__BOOL,
         Agg_MAX__INT8__INT8,
diff --git a/partiql-spi/src/main/kotlin/org/partiql/spi/connector/sql/builtins/AggCount.kt b/partiql-spi/src/main/kotlin/org/partiql/spi/connector/sql/builtins/AggCount.kt
index 8264a5f807..63dc2be90c 100644
--- a/partiql-spi/src/main/kotlin/org/partiql/spi/connector/sql/builtins/AggCount.kt
+++ b/partiql-spi/src/main/kotlin/org/partiql/spi/connector/sql/builtins/AggCount.kt
@@ -13,7 +13,7 @@ import org.partiql.value.PartiQLValueType.ANY
 import org.partiql.value.PartiQLValueType.INT64
 
 @OptIn(PartiQLValueExperimental::class, FnExperimental::class)
-public object Agg_COUNT__ANY__INT32 : Agg {
+public object Agg_COUNT__ANY__INT64 : Agg {
 
     override val signature: AggSignature = AggSignature(
         name = "count",
diff --git a/partiql-spi/src/main/kotlin/org/partiql/spi/connector/sql/builtins/AggCountStar.kt b/partiql-spi/src/main/kotlin/org/partiql/spi/connector/sql/builtins/AggCountStar.kt
deleted file mode 100644
index cb63fc7411..0000000000
--- a/partiql-spi/src/main/kotlin/org/partiql/spi/connector/sql/builtins/AggCountStar.kt
+++ /dev/null
@@ -1,25 +0,0 @@
-// ktlint-disable filename
-@file:Suppress("ClassName")
-
-package org.partiql.spi.connector.sql.builtins
-
-import org.partiql.spi.connector.sql.builtins.internal.AccumulatorCountStar
-import org.partiql.spi.fn.Agg
-import org.partiql.spi.fn.AggSignature
-import org.partiql.spi.fn.FnExperimental
-import org.partiql.value.PartiQLValueExperimental
-import org.partiql.value.PartiQLValueType.INT64
-
-@OptIn(PartiQLValueExperimental::class, FnExperimental::class)
-public object Agg_COUNT_STAR____INT32 : Agg {
-
-    override val signature: AggSignature = AggSignature(
-        name = "count_star",
-        returns = INT64,
-        parameters = listOf(),
-        isNullable = false,
-        isDecomposable = true
-    )
-
-    override fun accumulator(): Agg.Accumulator = AccumulatorCountStar()
-}