[CALCITE-6021] Add CURRENT_DATETIME function (enabled in BigQuery lib…

…rary) Co-authored-by: Julian Hyde <jhyde@apache.org> Co-authored-by: Tanner Clary <tannerclary@google.com>
looker-open-source · Oct 12, 2023 · db60219 · db60219
1 parent 77b3689
commit db60219
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Showing 10 changed files with 119 additions and 34 deletions.
diff --git a/babel/src/test/resources/sql/big-query.iq b/babel/src/test/resources/sql/big-query.iq
@@ -148,23 +148,25 @@ SELECT current_date() AS the_date, t.current_date FROM t;
 #
 # Returns DATETIME
 
-!if (false) {
-SELECT CURRENT_DATETIME() as now;
-+----------------------------+
-| now                        |
-+----------------------------+
-| 2016-05-19T10:38:47.046465 |
-+----------------------------+
+SELECT CURRENT_DATETIME() > DATETIME '2008-12-25 15:30:00' as now;
++------+
+| now  |
++------+
+| true |
++------+
+(1 row)
+
 !ok
 
-SELECT CURRENT_DATETIME as now;
-+----------------------------+
-| now                        |
-+----------------------------+
-| 2016-05-19T10:38:47.046465 |
-+----------------------------+
+SELECT CURRENT_DATETIME > DATETIME '2008-12-25 15:30:00' as now;
++------+
+| now  |
++------+
+| true |
++------+
+(1 row)
+
 !ok
-!}
 
 # When a column named current_datetime is present, the column name and
 # the function call without parentheses are ambiguous. To ensure the
@@ -173,16 +175,26 @@ SELECT CURRENT_DATETIME as now;
 # select the function in the now column and the table column in the
 # current_datetime column.
 
-!if (false) {
 WITH t AS (SELECT 'column value' AS `current_datetime`)
-SELECT current_datetime() as now, t.current_datetime FROM t;
-+----------------------------+------------------+
-| now                        | current_datetime |
-+----------------------------+------------------+
-| 2016-05-19T10:38:47.046465 | column value     |
-+----------------------------+------------------+
+SELECT current_datetime() > DATETIME '2008-12-25 15:30:00' as now, t.current_datetime FROM t;
++------+------------------+
+| now  | current_datetime |
++------+------------------+
+| true | column value     |
++------+------------------+
+(1 row)
+
+!ok
+
+SELECT CURRENT_DATETIME('UTC') > DATETIME '2008-12-25 15:30:00';
++--------+
+| EXPR$0 |
++--------+
+| true   |
++--------+
+(1 row)
+
 !ok
-!}
 
 #####################################################################
 # CURRENT_TIME

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
@@ -163,6 +163,7 @@
 import static org.apache.calcite.sql.fun.SqlLibraryOperators.COTH;
 import static org.apache.calcite.sql.fun.SqlLibraryOperators.CSC;
 import static org.apache.calcite.sql.fun.SqlLibraryOperators.CSCH;
+import static org.apache.calcite.sql.fun.SqlLibraryOperators.CURRENT_DATETIME;
 import static org.apache.calcite.sql.fun.SqlLibraryOperators.DATE;
 import static org.apache.calcite.sql.fun.SqlLibraryOperators.DATEADD;
 import static org.apache.calcite.sql.fun.SqlLibraryOperators.DATETIME;
@@ -1002,6 +1003,7 @@ Builder populate3() {
       map.put(CURRENT_TIME, systemFunctionImplementor);
       map.put(CURRENT_TIMESTAMP, systemFunctionImplementor);
       map.put(CURRENT_DATE, systemFunctionImplementor);
+      map.put(CURRENT_DATETIME, systemFunctionImplementor);
       map.put(LOCALTIME, systemFunctionImplementor);
       map.put(LOCALTIMESTAMP, systemFunctionImplementor);
 
@@ -3482,6 +3484,13 @@ private static class SystemFunctionImplementor
         return Expressions.call(BuiltInMethod.CURRENT_TIME.method, root);
       } else if (op == CURRENT_DATE) {
         return Expressions.call(BuiltInMethod.CURRENT_DATE.method, root);
+      } else if (op == CURRENT_DATETIME) {
+        if (call.getOperands().isEmpty()) {
+          return Expressions.call(BuiltInMethod.CURRENT_DATETIME.method, root);
+        } else {
+          return Expressions.call(BuiltInMethod.CURRENT_DATETIME2.method, root,
+            argValueList.get(0));
+        }
       } else if (op == LOCALTIMESTAMP) {
         return Expressions.call(BuiltInMethod.LOCAL_TIMESTAMP.method, root);
       } else if (op == LOCALTIME) {

diff --git a/core/src/main/java/org/apache/calcite/runtime/SqlFunctions.java b/core/src/main/java/org/apache/calcite/runtime/SqlFunctions.java
@@ -4708,6 +4708,23 @@ public static int currentDate(DataContext root) {
     return date;
   }
 
+  /** SQL {@code CURRENT_DATETIME} function. */
+  @NonDeterministic
+  public static Long currentDatetime(DataContext root) {
+    final long timestamp = DataContext.Variable.CURRENT_TIMESTAMP.get(root);
+    return datetime(timestamp);
+  }
+
+  /** SQL {@code CURRENT_DATETIME} function with a specified timezone. */
+  @NonDeterministic
+  public static @Nullable Long currentDatetime(DataContext root, @Nullable String timezone) {
+    if (timezone == null) {
+      return null;
+    }
+    final long timestamp = DataContext.Variable.UTC_TIMESTAMP.get(root);
+    return datetime(timestamp, timezone);
+  }
+
   /** SQL {@code LOCAL_TIMESTAMP} function. */
   @NonDeterministic
   public static long localTimestamp(DataContext root) {

diff --git a/core/src/main/java/org/apache/calcite/sql/SqlSyntax.java b/core/src/main/java/org/apache/calcite/sql/SqlSyntax.java
@@ -136,7 +136,7 @@ public enum SqlSyntax {
    *
    * @see SqlConformance#allowNiladicParentheses()
    */
-  FUNCTION_ID {
+  FUNCTION_ID(FUNCTION) {
     @Override public void unparse(
         SqlWriter writer,
         SqlOperator operator,

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
@@ -801,9 +801,10 @@ static RelDataType deriveTypeSplit(SqlOperatorBinding operatorBinding,
   @LibraryOperator(libraries = {BIG_QUERY})
   public static final SqlFunction CURRENT_DATETIME =
       SqlBasicFunction.create("CURRENT_DATETIME",
-          ReturnTypes.TIMESTAMP.andThen(SqlTypeTransforms.TO_NULLABLE),
+          ReturnTypes.TIMESTAMP_NULLABLE,
           OperandTypes.NILADIC.or(OperandTypes.STRING),
-          SqlFunctionCategory.TIMEDATE);
+          SqlFunctionCategory.TIMEDATE)
+          .withSyntax(SqlSyntax.FUNCTION_ID);
 
   /** The "DATE_FROM_UNIX_DATE(integer)" function; returns a DATE value
    * a given number of seconds after 1970-01-01. */

diff --git a/core/src/main/java/org/apache/calcite/sql/util/ListSqlOperatorTable.java b/core/src/main/java/org/apache/calcite/sql/util/ListSqlOperatorTable.java
@@ -79,20 +79,24 @@ public void add(SqlOperator op) {
       SqlSyntax syntax,
       List<SqlOperator> operatorList,
       SqlNameMatcher nameMatcher) {
-    for (SqlOperator operator : this.operatorList) {
-      if (operator.getSyntax().family != syntax) {
-        continue;
-      }
+    for (SqlOperator op : this.operatorList) {
       if (!opName.isSimple()
-          || !nameMatcher.matches(operator.getName(), opName.getSimple())) {
+          || !nameMatcher.matches(op.getName(), opName.getSimple())) {
         continue;
       }
       if (category != null
-          && category != category(operator)
+          && category != category(op)
           && !category.isUserDefinedNotSpecificFunction()) {
         continue;
       }
-      operatorList.add(operator);
+      if (op.getSyntax() == syntax) {
+        operatorList.add(op);
+      } else if (syntax == SqlSyntax.FUNCTION
+          && op instanceof SqlFunction) {
+        // this special case is needed for operators like CAST,
+        // which are treated as functions but have special syntax
+        operatorList.add(op);
+      }
     }
   }
 

diff --git a/core/src/main/java/org/apache/calcite/util/BuiltInMethod.java b/core/src/main/java/org/apache/calcite/util/BuiltInMethod.java
@@ -684,6 +684,9 @@ public enum BuiltInMethod {
   CURRENT_TIMESTAMP(SqlFunctions.class, "currentTimestamp", DataContext.class),
   CURRENT_TIME(SqlFunctions.class, "currentTime", DataContext.class),
   CURRENT_DATE(SqlFunctions.class, "currentDate", DataContext.class),
+  CURRENT_DATETIME(SqlFunctions.class, "currentDatetime", DataContext.class),
+  CURRENT_DATETIME2(SqlFunctions.class, "currentDatetime", DataContext.class,
+      String.class),
   LOCAL_TIMESTAMP(SqlFunctions.class, "localTimestamp", DataContext.class),
   LOCAL_TIME(SqlFunctions.class, "localTime", DataContext.class),
   TIME_ZONE(SqlFunctions.class, "timeZone", DataContext.class),

diff --git a/core/src/test/java/org/apache/calcite/plan/RelWriterTest.java b/core/src/test/java/org/apache/calcite/plan/RelWriterTest.java
@@ -1047,7 +1047,7 @@ void testAggregateWithAlias(SqlExplainFormat format) {
     String relJson = jsonWriter.asString();
     String result = deserializeAndDumpToTextFormat(getSchema(rel), relJson);
     final String expected = ""
-        + "LogicalProject(JOB=[$2], $f1=[CURRENT_DATETIME()])\n"
+        + "LogicalProject(JOB=[$2], $f1=[CURRENT_DATETIME])\n"
         + "  LogicalTableScan(table=[[scott, EMP]])\n";
     assertThat(result, isLinux(expected));
   }

diff --git a/core/src/test/java/org/apache/calcite/test/SqlValidatorTest.java b/core/src/test/java/org/apache/calcite/test/SqlValidatorTest.java
@@ -1615,6 +1615,9 @@ void testLikeAndSimilarFails() {
     shouldFail.fails("Column 'CURRENT_DATETIME' not found in any table");
 
     final SqlOperatorTable opTable = operatorTableFor(SqlLibrary.BIG_QUERY);
+    sql("select current_datetime")
+        .withConformance(SqlConformanceEnum.BIG_QUERY)
+        .withOperatorTable(opTable).ok();
     sql("select current_datetime()")
         .withConformance(SqlConformanceEnum.BIG_QUERY)
         .withOperatorTable(opTable).ok();

diff --git a/testkit/src/main/java/org/apache/calcite/test/SqlOperatorTest.java b/testkit/src/main/java/org/apache/calcite/test/SqlOperatorTest.java
@@ -6986,9 +6986,45 @@ private static void checkIf(SqlOperatorFixture f) {
     // allow it as a function.
     f.checkNull("DATE(null)");
     f.checkScalar("DATE('1985-12-06')", "1985-12-06", "DATE NOT NULL");
+  }
+
+  /** Tests that the {@code CURRENT_DATETIME} function is defined in the
+   * BigQuery library, is not available in the default library,
+   * and can be called with and without parentheses. */
+  @Test void testCurrentDatetimeFunc() {
+    SqlOperatorFixture f0 = fixture()
+        .setFor(SqlLibraryOperators.CURRENT_DATETIME);
+
+    // In default conformance, with BigQuery operator table,
+    // CURRENT_DATETIME is valid only without parentheses.
+    final SqlOperatorFixture f1 =
+        f0.withLibrary(SqlLibrary.BIG_QUERY);
+    f1.checkType("CURRENT_DATETIME", "TIMESTAMP(0) NOT NULL");
+    f1.checkFails("^CURRENT_DATETIME()^",
+        "No match found for function signature CURRENT_DATETIME\\(\\)",
+        false);
+
+    // In BigQuery conformance, with BigQuery operator table,
+    // CURRENT_DATETIME should be valid with and without parentheses.
+    // We cannot execute it because results are non-deterministic.
+    SqlOperatorFixture f =
+        f1.withConformance(SqlConformanceEnum.BIG_QUERY);
+    f.checkType("CURRENT_DATETIME", "TIMESTAMP(0) NOT NULL");
     f.checkType("CURRENT_DATETIME()", "TIMESTAMP(0) NOT NULL");
-    f.checkType("CURRENT_DATETIME('America/Los_Angeles')", "TIMESTAMP(0) NOT NULL");
+    f.checkType("CURRENT_DATETIME('America/Los_Angeles')",
+        "TIMESTAMP(0) NOT NULL");
     f.checkType("CURRENT_DATETIME(CAST(NULL AS VARCHAR(20)))", "TIMESTAMP(0)");
+    f.checkNull("CURRENT_DATETIME(CAST(NULL AS VARCHAR(20)))");
+
+    // In BigQuery conformance, but with the default operator table,
+    // CURRENT_DATETIME is not found.
+    final SqlOperatorFixture f2 =
+        f0.withConformance(SqlConformanceEnum.BIG_QUERY);
+    f2.checkFails("^CURRENT_DATETIME^",
+        "Column 'CURRENT_DATETIME' not found in any table", false);
+    f2.checkFails("^CURRENT_DATETIME()^",
+        "No match found for function signature CURRENT_DATETIME\\(\\)",
+        false);
   }
 
   @Test void testAbsFunc() {