Fix Datapart functions to be Timezone Invariant (babelfish-for-postgr…

…esql#3226)

We were incorrectly passing timezone to timestamp2tm function which would cause the datepart functions to be timezone dependent , If we pass tzp by reference to timestamp2tm function, then internally localtime converts the given original timestamp value to date and time values adding timezone offset taking GMT as a reference timezone. However, if NULL is passed instead then we keep the original timestamp intact and that's what actually PG does.

Issues Resolved
BABEL-5453

Signed-off-by: Nirmit Shah [email protected]

contrib/babelfishpg_tsql/runtime/functions.c

@@ -373,7 +373,6 @@ datepart_internal(char* field, Timestamp timestamp, float8 df_tz, bool general_i
 	Timestamp	tsql_first_day, first_day;
 	struct pg_tm tt1, *tm = &tt1;
 	uint		first_week_end, year, month, day, res = 0, day_of_year; /* for Zeller's Congruence */
-	int 		tz1;
 
 	/*
 	 * This block is used when the second argument in datepart is not a 
@@ -396,7 +395,7 @@ datepart_internal(char* field, Timestamp timestamp, float8 df_tz, bool general_i
 	}
 
 	/* Gets the date time related fields back from timestamp into struct tm pointer */
-	if (timestamp2tm(timestamp, &tz1, tm, &fsec1, NULL, NULL) != 0)
+	if (timestamp2tm(timestamp, NULL, tm, &fsec1, NULL, NULL) != 0)
 	{
 		ereport(ERROR,
 			(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),

test/JDBC/expected/datepart-vu-cleanup.out

@@ -18,3 +18,6 @@ GO
 
 DROP PROCEDURE date_part_vu_prepare_sys_day_proc
 GO
+
+DROP TABLE date_part_vu_prepare_TestDates, date_part_vu_prepare_TestTimezones, date_part_vu_prepare_TestResults, date_part_vu_prepare_DateParts;
+GO

test/JDBC/expected/datepart-vu-prepare.out

@@ -43,3 +43,47 @@ CREATE PROCEDURE date_part_vu_prepare_sys_day_proc @a datetime
 AS
 SELECT DAY(@a)
 GO
+
+-- Test Case for Date Part Functions Timezone Invariance
+CREATE TABLE date_part_vu_prepare_DateParts (DatePartName VARCHAR(20));
+GO
+CREATE TABLE date_part_vu_prepare_TestDates (
+    TestDateTime DATETIME,
+    TestDateTimeOffset DATETIMEOFFSET,
+    TestDateTime2 DATETIME2,
+    TestSmallDateTime SMALLDATETIME
+);
+GO
+CREATE TABLE date_part_vu_prepare_TestTimezones (TimezoneName VARCHAR(50));
+GO
+CREATE TABLE date_part_vu_prepare_TestResults (
+    TestCase VARCHAR(100),
+    TimeZone VARCHAR(50),
+    DataType VARCHAR(20),
+    InputDate VARCHAR(50),
+    DatePart VARCHAR(20),
+    DatePartValue SQL_VARIANT,
+    DateName NVARCHAR(100)
+);
+GO
+
+-- -- Populate tables
+INSERT INTO date_part_vu_prepare_DateParts (DatePartName) VALUES
+('year'), ('quarter'), ('month'), ('dayofyear'), ('day'), 
+('week'), ('weekday'), ('hour'), ('minute'), ('second'), 
+('millisecond'), ('microsecond'), ('nanosecond'),
+('tzoffset'), ('iso_week');
+GO
+~~ROW COUNT: 15~~
+
+INSERT INTO date_part_vu_prepare_TestDates VALUES 
+('2025-01-01 05:30:45', '2025-01-01 05:30:45 +00:00', '2025-01-01 05:30:45.1234567', '2025-01-01 05:31:00'),
+('2025-06-15 23:59:59', '2025-06-15 23:59:59 +00:00', '2025-06-15 23:59:59.9876543', '2025-06-15 23:59:00');
+GO
+~~ROW COUNT: 2~~
+
+INSERT INTO date_part_vu_prepare_TestTimezones (TimezoneName) VALUES
+('UTC'),('America/New_York'), ('Europe/London'), ('Asia/Tokyo'), ('Africa/Nairobi');
+GO
+~~ROW COUNT: 5~~
+