[CALCITE-6766] Move DATEADD and DATEDIFF from PostgreSQL to Redshift …

…library

babel/src/test/java/org/apache/calcite/test/BabelParserTest.java

@@ -189,8 +189,8 @@ class BabelParserTest extends SqlParserTest {
     sql("select date(x) from t").ok(expected);
   }
 
-  /** In Redshift, PostgreSQL the DATEADD, DATEDIFF and DATE_PART functions have
-   * ordinary function syntax except that its first argument is a time unit
+  /** The DATEADD, DATEDIFF (in Redshift, Snowflake) and DATE_PART (in PostgreSQL)
+   * functions have ordinary function syntax  except that its first argument is a time unit
    * (e.g. DAY). We must not parse that first argument as an identifier. */
   @Test void testRedshiftFunctionsWithDateParts() {
     final String sql = "SELECT DATEADD(day, 1, t),\n"

core/src/main/java/org/apache/calcite/sql/fun/SqlLibraryOperators.java

@@ -128,7 +128,7 @@ private SqlLibraryOperators() {
 
   /** The "DATEADD(timeUnit, numeric, datetime)" function
    * (Microsoft SQL Server, Redshift, Snowflake). */
-  @LibraryOperator(libraries = {MSSQL, POSTGRESQL})
+  @LibraryOperator(libraries = {MSSQL, REDSHIFT, SNOWFLAKE})
   public static final SqlFunction DATEADD =
       new SqlTimestampAddFunction("DATEADD");
 
@@ -162,7 +162,7 @@ private SqlLibraryOperators() {
    * <p>MySQL has "DATEDIFF(date, date2)" and "TIMEDIFF(time, time2)" functions
    * but Calcite does not implement these because they have no "timeUnit"
    * argument. */
-  @LibraryOperator(libraries = {MSSQL, POSTGRESQL})
+  @LibraryOperator(libraries = {MSSQL, REDSHIFT, SNOWFLAKE})
   public static final SqlFunction DATEDIFF =
       new SqlTimestampDiffFunction("DATEDIFF",
           OperandTypes.family(SqlTypeFamily.ANY, SqlTypeFamily.DATE,

site/_docs/reference.md

@@ -2851,8 +2851,8 @@ In the following:
 | b | DATE(timestampLtz, timeZone)                   | Extracts the DATE from *timestampLtz* (an instant; BigQuery's TIMESTAMP type) in *timeZone*
 | b | DATE(string)                                   | Equivalent to `CAST(string AS DATE)`
 | b | DATE(year, month, day)                         | Returns a DATE value for *year*, *month*, and *day* (all of type INTEGER)
-| p q r | DATEADD(timeUnit, integer, datetime)       | Equivalent to `TIMESTAMPADD(timeUnit, integer, datetime)`
-| p q r | DATEDIFF(timeUnit, datetime, datetime2)    | Equivalent to `TIMESTAMPDIFF(timeUnit, datetime, datetime2)`
+| q r f | DATEADD(timeUnit, integer, datetime)       | Equivalent to `TIMESTAMPADD(timeUnit, integer, datetime)`
+| q r f | DATEDIFF(timeUnit, datetime, datetime2)    | Equivalent to `TIMESTAMPDIFF(timeUnit, datetime, datetime2)`
 | q | DATEPART(timeUnit, datetime)                   | Equivalent to `EXTRACT(timeUnit FROM  datetime)`
 | b | DATETIME(date, time)                           | Converts *date* and *time* to a TIMESTAMP
 | b | DATETIME(date)                                 | Converts *date* to a TIMESTAMP value (at midnight)
@@ -3035,10 +3035,6 @@ In the following:
 
 Note:
 
-* Calcite has no Redshift library, so the Postgres library
-  is used instead. The functions `DATEADD`, `DATEDIFF` are
-  implemented in Redshift and not Postgres but nevertheless
-  appear in Calcite's Postgres library
 * Functions `DATEADD`, `DATEDIFF`, `DATE_PART` require the Babel parser
 * `JSON_TYPE` / `JSON_DEPTH` / `JSON_PRETTY` / `JSON_STORAGE_SIZE` return null if the argument is null
 * `JSON_LENGTH` / `JSON_KEYS` / `JSON_REMOVE` return null if the first argument is null