[CALCITE-6325] Add LOG function (enabled in Mysql library)

apache · Mar 19, 2024 · adcbe2e · adcbe2e
1 parent 4b946b9
commit adcbe2e
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Showing 5 changed files with 20 additions and 15 deletions.
diff --git a/core/src/main/java/org/apache/calcite/adapter/enumerable/RexImpTable.java b/core/src/main/java/org/apache/calcite/adapter/enumerable/RexImpTable.java
@@ -644,12 +644,15 @@ Builder populate() {
       defineMethod(POWER, BuiltInMethod.POWER.method, NullPolicy.STRICT);
       defineMethod(ABS, BuiltInMethod.ABS.method, NullPolicy.STRICT);
 
-      map.put(LN, new LogImplementor(BuiltInMethod.LOG.method));
-      map.put(LOG, new LogImplementor(BuiltInMethod.LOG.method));
-      map.put(LOG10, new LogImplementor(BuiltInMethod.LOG.method));
-
-      map.put(LOG_MYSQL_SPARK, new LogImplementor(BuiltInMethod.LOG_MYSQL_SPARK.method));
-      map.put(LOG2, new LogImplementor(BuiltInMethod.LOG_MYSQL_SPARK.method));
+      LogImplementor logImplementor = new LogImplementor(BuiltInMethod.LOG.method);
+      map.put(LN, logImplementor);
+      map.put(LOG, logImplementor);
+      map.put(LOG10, logImplementor);
+
+      LogImplementor logMysqlSparkImplementor =
+          new LogImplementor(BuiltInMethod.LOG_MYSQL_SPARK.method);
+      map.put(LOG_MYSQL_SPARK, logMysqlSparkImplementor);
+      map.put(LOG2, logMysqlSparkImplementor);
 
       defineReflective(RAND, BuiltInMethod.RAND.method,
           BuiltInMethod.RAND_SEED.method);

diff --git a/core/src/main/java/org/apache/calcite/runtime/SqlFunctions.java b/core/src/main/java/org/apache/calcite/runtime/SqlFunctions.java
@@ -2788,24 +2788,26 @@ public static double log(BigDecimal d0, BigDecimal d1) {
     return Math.log(d0.doubleValue()) / Math.log(d1.doubleValue());
   }
 
-  /** SQL {@code LOGMySqlSpark(number, number2)} function applied to double values. */
+  /** SQL {@code LOG(number, number2)} function applied to double values.
+   * but return null when number2 is 0. */
   public static @Nullable Double logMysqlSpark(double number, double number2) {
     return (number <= 0) ? null : log(number, number2);
   }
 
-  /** SQL {@code LOGMySqlSpark(number, number2)} function applied to
-   * double and BigDecimal values. */
+  /** SQL {@code LOG(number, number2)} function applied to double and BigDecimal values.
+   * but return null when number2 is 0. */
   public static @Nullable Double logMysqlSpark(double number, BigDecimal number2) {
     return logMysqlSpark(number, number2.doubleValue());
   }
 
-  /** SQL {@code LOGMySqlSpark(number, number2)} function applied to
-   * BigDecimal and double values. */
+  /** SQL {@code LOG(number, number2)} function applied to BigDecimal and double values.
+   * but return null when number2 is 0. */
   public static @Nullable Double logMysqlSpark(BigDecimal number, double number2) {
     return logMysqlSpark(number.doubleValue(), number2);
   }
 
-  /** SQL {@code LOGMySqlSpark(number, number2)} function applied to double values. */
+  /** SQL {@code LOG(number, number2)} function applied to double values.
+   * but return null when number2 is 0. */
   public static @Nullable Double logMysqlSpark(BigDecimal number, BigDecimal number2) {
     return logMysqlSpark(number.doubleValue(), number2.doubleValue());
   }

diff --git a/core/src/main/java/org/apache/calcite/sql/fun/SqlLibraryOperators.java b/core/src/main/java/org/apache/calcite/sql/fun/SqlLibraryOperators.java
@@ -2205,7 +2205,7 @@ private static RelDataType deriveTypeMapFromEntries(SqlOperatorBinding opBinding
           OperandTypes.NUMERIC_OPTIONAL_NUMERIC,
           SqlFunctionCategory.NUMERIC);
 
-  /** The "LOG(numeric, numeric1)" function. Returns the base numeric1 logarithm of numeric. */
+  /** The "LOG(numeric1, numeric2)" function. Returns the base numeric1 logarithm of numeric. */
   @LibraryOperator(libraries = {MYSQL, SPARK})
   public static final SqlFunction LOG_MYSQL_SPARK =
       SqlBasicFunction.create("LOG",

diff --git a/site/_docs/reference.md b/site/_docs/reference.md
@@ -2785,7 +2785,7 @@ In the following:
 | b f s | LENGTH(string)                             | Equivalent to `CHAR_LENGTH(string)`
 | h s | LEVENSHTEIN(string1, string2)                | Returns the Levenshtein distance between *string1* and *string2*
 | b | LOG(numeric1 [, numeric2 ])                    | Returns the logarithm of *numeric1* to base *numeric2*, or base e if *numeric2* is not present
-| m s | LOG(numeric1 [, numeric2 ])                  | Returns the logarithm of *numeric1* to base *numeric2*, or base e if *numeric2* is not present
+| m s | LOG(numeric1 [, numeric2 ])                  | Returns the logarithm of *numeric1* to base *numeric2*, or base e if *numeric2* is not present but *numeric2* is zero returns NULL
 | m s | LOG2(numeric)                                | Returns the base 2 logarithm of *numeric*
 | b o s | LPAD(string, length [, pattern ])          | Returns a string or bytes value that consists of *string* prepended to *length* with *pattern*
 | b | TO_BASE32(string)                              | Converts the *string* to base-32 encoded form and returns an encoded string

diff --git a/testkit/src/main/java/org/apache/calcite/test/SqlOperatorTest.java b/testkit/src/main/java/org/apache/calcite/test/SqlOperatorTest.java
@@ -6340,7 +6340,7 @@ void checkRegexpExtract(SqlOperatorFixture f0, FunctionAlias functionAlias) {
 
   /** Test case for
    * <a href="https://issues.apache.org/jira/browse/CALCITE-6325">[CALCITE-6325]
-   * Add LOG function (enabled in MYSQL, Spark library)</a>. */
+   * Add LOG function (enabled in MYSQL library)</a>. */
   @Test void testLogMysqlSparkFunc() {
     final SqlOperatorFixture f0 = fixture();
     f0.checkFails("^log(100, 10)^",