[SPARK-52493][SQL] Support TIMESTAMP WITHOUT TIME ZONE

### What changes were proposed in this pull request?
In the PR, I propose to introduce a synonym for the existing type `TIMESTAMP_NTZ` as the SQL standard defines: `TIMESTAMP WITHOUT TIME ZONE`.

### Why are the changes needed?
- To conform to the SQL standard
- To simplify migration from other systems that recognize the fully qualified type name.
- To be consistent with the `TIME` type, see #51177

### Does this PR introduce _any_ user-facing change?
No, it just extends the existing syntax.

### How was this patch tested?
By running the modified test suite:
```
$ build/sbt "test:testOnly *DataTypeParserSuite"
```

### Was this patch authored or co-authored using generative AI tooling?
No.

Closes #51181 from MaxGekk/timestamp-without-timezone.

Authored-by: Max Gekk <[email protected]>
Signed-off-by: Max Gekk <[email protected]>

Author: MaxGekk

sql/api/src/main/antlr4/org/apache/spark/sql/catalyst/parser/SqlBaseParser.g4

@@ -1345,6 +1345,7 @@ dataType
       (TO to=(HOUR | MINUTE | SECOND))?                         #dayTimeIntervalDataType
     | TIME (LEFT_PAREN precision=INTEGER_VALUE RIGHT_PAREN)?
       (WITHOUT TIME ZONE)?                                      #timeDataType
+    | (TIMESTAMP_NTZ | TIMESTAMP WITHOUT TIME ZONE)             #timestampNtzDataType
     | type (LEFT_PAREN INTEGER_VALUE
       (COMMA INTEGER_VALUE)* RIGHT_PAREN)?                      #primitiveDataType
     ;

sql/api/src/main/scala/org/apache/spark/sql/catalyst/parser/DataTypeAstBuilder.scala

@@ -77,6 +77,13 @@ class DataTypeAstBuilder extends SqlBaseParserBaseVisitor[AnyRef] {
     TimeType(precision)
   }
 
+  /**
+   * Create the TIMESTAMP_NTZ primitive type.
+   */
+  override def visitTimestampNtzDataType(ctx: TimestampNtzDataTypeContext): DataType = {
+    withOrigin(ctx)(TimestampNTZType)
+  }
+
   /**
    * Resolve/create a primitive type.
    */
@@ -92,7 +99,6 @@ class DataTypeAstBuilder extends SqlBaseParserBaseVisitor[AnyRef] {
       case (DOUBLE, Nil) => DoubleType
       case (DATE, Nil) => DateType
       case (TIMESTAMP, Nil) => SqlApiConf.get.timestampType
-      case (TIMESTAMP_NTZ, Nil) => TimestampNTZType
       case (TIMESTAMP_LTZ, Nil) => TimestampType
       case (STRING, Nil) =>
         typeCtx.children.asScala.toSeq match {

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/parser/DataTypeParserSuite.scala

@@ -64,6 +64,7 @@ class DataTypeParserSuite extends SparkFunSuite with SQLHelper {
   checkDataType("TIME(6)", TimeType(6))
   checkDataType("TIME(6) WITHOUT TIME ZONE", TimeType(6))
   checkDataType("timestamp", TimestampType)
+  checkDataType("TIMESTAMP WITHOUT TIME ZONE", TimestampNTZType)
   checkDataType("timestamp_ntz", TimestampNTZType)
   checkDataType("timestamp_ltz", TimestampType)
   checkDataType("string", StringType)
@@ -160,6 +161,7 @@ class DataTypeParserSuite extends SparkFunSuite with SQLHelper {
     }
     withSQLConf(SQLConf.TIMESTAMP_TYPE.key -> TimestampTypes.TIMESTAMP_LTZ.toString) {
       assert(parse("timestamp") === TimestampType)
+      assert(parse("timestamp without time zone") === TimestampNTZType)
     }
   }
 
@@ -220,4 +222,19 @@ class DataTypeParserSuite extends SparkFunSuite with SQLHelper {
       condition = "PARSE_SYNTAX_ERROR",
       parameters = Map("error" -> "'WITH'", "hint" -> ""))
   }
+
+  test("invalid TIMESTAMP suffix") {
+    checkError(
+      exception = intercept[ParseException] {
+        CatalystSqlParser.parseDataType("timestamp WITHOUT TIMEZONE")
+      },
+      condition = "PARSE_SYNTAX_ERROR",
+      parameters = Map("error" -> "'WITHOUT'", "hint" -> ""))
+    checkError(
+      exception = intercept[ParseException] {
+        CatalystSqlParser.parseDataType("timestamp WITH TIME ZONE")
+      },
+      condition = "PARSE_SYNTAX_ERROR",
+      parameters = Map("error" -> "'WITH'", "hint" -> ""))
+  }
 }