From 1245db620114ee5174641ad540af6b27dcd772e3 Mon Sep 17 00:00:00 2001
From: wenrui <wenrui@singleorigin.tech>
Date: Fri, 22 Sep 2023 22:56:53 -0700
Subject: [PATCH] [CALCITE-6007] Sub-query that contains WITH and has no alias
 generates invalid SQL after expansion

Add Quidem test (Julian Hyde).

Close apache/calcite#3440
---
 .../sql/validate/SqlValidatorImpl.java        |  2 +-
 .../apache/calcite/test/SqlValidatorTest.java | 19 +++++++++++++
 core/src/test/resources/sql/misc.iq           | 28 +++++++++++++++++++
 3 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/core/src/main/java/org/apache/calcite/sql/validate/SqlValidatorImpl.java b/core/src/main/java/org/apache/calcite/sql/validate/SqlValidatorImpl.java
index 83fbc513826..75eb3637edd 100644
--- a/core/src/main/java/org/apache/calcite/sql/validate/SqlValidatorImpl.java
+++ b/core/src/main/java/org/apache/calcite/sql/validate/SqlValidatorImpl.java
@@ -2350,7 +2350,7 @@ private SqlNode registerFrom(
       case PIVOT:
       case UNPIVOT:
       case MATCH_RECOGNIZE:
-
+      case WITH:
         // give this anonymous construct a name since later
         // query processing stages rely on it
         alias = SqlValidatorUtil.alias(node, nextGeneratedId++);
diff --git a/core/src/test/java/org/apache/calcite/test/SqlValidatorTest.java b/core/src/test/java/org/apache/calcite/test/SqlValidatorTest.java
index 150dbdf7853..8f0d1c002f7 100644
--- a/core/src/test/java/org/apache/calcite/test/SqlValidatorTest.java
+++ b/core/src/test/java/org/apache/calcite/test/SqlValidatorTest.java
@@ -7993,6 +7993,25 @@ void testGroupExpressionEquivalenceParams() {
             + "FROM `DEPT`");
   }
 
+  /** Test case for
+   * <a href="https://issues.apache.org/jira/browse/CALCITE-6007">[CALCITE-6007]
+   * Sub-query that contains WITH and has no alias generates invalid SQL after
+   * expansion</a>. */
+  @Test void testSubQueryWithoutAlias() {
+    // Note the 'AS `EXPR$0`' in the rewritten form of each query.
+    // Before [CALCITE-6007] was fixed, that alias was missing.
+    sql("select a from (select 1 as a)")
+        .withValidatorIdentifierExpansion(true)
+        .rewritesTo("SELECT `EXPR$0`.`A`\n"
+            + "FROM (SELECT 1 AS `A`) AS `EXPR$0`");
+    sql("select a from (with sub as (select 1 as a) select a from sub)")
+        .withValidatorIdentifierExpansion(true)
+        .rewritesTo("SELECT `EXPR$0`.`A`\n"
+            + "FROM (WITH `SUB` AS (SELECT 1 AS `A`) "
+            + "SELECT `SUB`.`A`\n"
+            + "FROM `SUB` AS `SUB`) AS `EXPR$0`");
+  }
+
   /** Test case for
    * <a href="https://issues.apache.org/jira/browse/CALCITE-1238">[CALCITE-1238]
    * Unparsing LIMIT without ORDER BY after validation</a>. */
diff --git a/core/src/test/resources/sql/misc.iq b/core/src/test/resources/sql/misc.iq
index 65fe7f085da..9876587d196 100644
--- a/core/src/test/resources/sql/misc.iq
+++ b/core/src/test/resources/sql/misc.iq
@@ -796,6 +796,34 @@ having exists
 
 !ok
 
+# [CALCITE-6007] Sub-query that contains WITH and has no alias generates invalid SQL after expansion
+SELECT a, b
+FROM (
+  WITH sub AS (SELECT 1 AS a, 2 AS b)
+  SELECT * FROM sub)
+WHERE a IS NOT NULL;
++---+---+
+| A | B |
++---+---+
+| 1 | 2 |
++---+---+
+(1 row)
+
+!ok
+
+# Similar pattern to previous, without WITH
+SELECT a, b
+FROM (SELECT 1 AS a, 2 AS b)
+WHERE a IS NOT NULL;
++---+---+
+| A | B |
++---+---+
+| 1 | 2 |
++---+---+
+(1 row)
+
+!ok
+
 # [CALCITE-411] Duplicate aliases
 select 1 as a, 2 as a from (values (true));
 +---+---+