support DATETRUNC() function

contrib/babelfishpg_tsql/antlr/TSqlLexer.g4

@@ -243,6 +243,7 @@ DATEFORMAT:                                      D A T E F O R M A T;
 DATE_FORMAT:                                     D A T E  UNDERLINE  F O R M A T;
 DATENAME:                                        D A T E N A M E;
 DATEPART:                                        D A T E P A R T;
+DATETRUNC:                                       D A T E T R U N C;
 DATE_CORRELATION_OPTIMIZATION:                   D A T E  UNDERLINE  C O R R E L A T I O N  UNDERLINE  O P T I M I Z A T I O N;
 DAY:                                             D A Y;
 DAYS:                                            D A Y S;

contrib/babelfishpg_tsql/antlr/TSqlParser.g4

@@ -4338,6 +4338,7 @@ keyword
     | DATE_FORMAT
     | DATENAME
     | DATEPART
+    | DATETRUNC
     | DATE_CORRELATION_OPTIMIZATION
     | DATE_FORMAT
     | DAY

contrib/babelfishpg_tsql/sql/sys_functions.sql

@@ -4418,3 +4418,109 @@ BEGIN
 END;
 $body$
 LANGUAGE plpgsql IMMUTABLE;
+
+CREATE OR REPLACE FUNCTION sys.DATETRUNC(IN datepart PG_CATALOG.TEXT, IN date ANYELEMENT) RETURNS ANYELEMENT AS
+$body$
+DECLARE
+    days_offset INT;
+    v_day INT;
+    result_date timestamp;
+    input_expr_timestamp timestamp;
+    date_arg_datatype regtype;
+    offset_string PG_CATALOG.TEXT;
+    datefirst_value INT;
+BEGIN
+    BEGIN
+        /* perform input validation */
+        date_arg_datatype := pg_typeof(date);
+        IF datepart NOT IN ('year', 'quarter', 'month', 'week', 'tsql_week', 'hour', 'minute', 'second', 'millisecond', 'microsecond', 
+                            'doy', 'day', 'nanosecond', 'tzoffset') THEN
+            RAISE EXCEPTION '''%'' is not a recognized datetrunc option.', datepart;
+        ELSIF date_arg_datatype NOT IN ('date'::regtype, 'time'::regtype, 'sys.datetime'::regtype, 'sys.datetime2'::regtype,
+                                        'sys.datetimeoffset'::regtype, 'sys.smalldatetime'::regtype) THEN
+            RAISE EXCEPTION 'Argument data type ''%'' is invalid for argument 2 of datetrunc function.', date_arg_datatype;
+        ELSIF datepart IN ('nanosecond', 'tzoffset') THEN
+            RAISE EXCEPTION 'The datepart ''%'' is not supported by date function datetrunc for data type ''%''.',datepart, date_arg_datatype;
+        ELSIF datepart IN ('dow') THEN
+            RAISE EXCEPTION 'The datepart ''weekday'' is not supported by date function datetrunc for data type ''%''.', date_arg_datatype;
+        ELSIF date_arg_datatype = 'date'::regtype AND datepart IN ('hour', 'minute', 'second', 'millisecond', 'microsecond') THEN
+            RAISE EXCEPTION 'The datepart ''%'' is not supported by date function datetrunc for data type ''date''.', datepart;
+        ELSIF date_arg_datatype = 'datetime'::regtype AND datepart IN ('microsecond') THEN
+            RAISE EXCEPTION 'The datepart ''%'' is not supported by date function datetrunc for data type ''datetime''.', datepart;
+        ELSIF date_arg_datatype = 'smalldatetime'::regtype AND datepart IN ('millisecond', 'microsecond') THEN
+            RAISE EXCEPTION 'The datepart ''%'' is not supported by date function datetrunc for data type ''smalldatetime''.', datepart;
+        ELSIF date_arg_datatype = 'time'::regtype THEN
+            IF datepart IN ('year', 'quarter', 'month', 'doy', 'day', 'week', 'tsql_week') THEN
+                RAISE EXCEPTION 'The datepart ''%'' is not supported by date function datetrunc for data type ''time''.', datepart;
+            END IF;
+            -- Limitation in determining if the specified fractional scale (if provided any) for time datatype is 
+            -- insufficient to support provided datepart (millisecond, microsecond) value
+        ELSIF date_arg_datatype IN ('datetime2'::regtype, 'datetimeoffset'::regtype) THEN
+            -- Limitation in determining if the specified fractional scale (if provided any) for the above datatype is
+            -- insufficient to support for provided datepart (millisecond, microsecond) value
+        END IF;
+
+        /* input validation is complete, proceed with result calculation. */
+        IF date_arg_datatype = 'time'::regtype THEN
+            RETURN date_trunc(datepart, date);
+        ELSE
+            input_expr_timestamp = date::timestamp;
+            -- preserving offset_string value in the case of datetimeoffset datatype before converting it to timestamps 
+            IF date_arg_datatype = 'sys.datetimeoffset'::regtype THEN
+                offset_string = RIGHT(date::PG_CATALOG.TEXT, 6);
+                input_expr_timestamp := LEFT(date::PG_CATALOG.TEXT, -6)::timestamp;
+            END IF;
+            CASE
+                WHEN datepart IN ('year', 'quarter', 'month', 'week', 'hour', 'minute', 'second', 'millisecond', 'microsecond')  THEN
+                    result_date := date_trunc(datepart, input_expr_timestamp);
+                WHEN datepart IN ('doy', 'day') THEN
+                    result_date := date_trunc('day', input_expr_timestamp);
+                WHEN datepart IN ('tsql_week') THEN
+                -- sql server datepart 'iso_week' is similar to postgres 'week' datepart
+                -- handle sql server datepart 'week' here based on the value of set variable 'DATEFIRST'
+                    v_day := EXTRACT(dow from input_expr_timestamp)::INT;
+                    datefirst_value := current_setting('babelfishpg_tsql.datefirst')::INT;
+                    IF v_day = 0 THEN
+                        v_day := 7;
+                    END IF;
+                    result_date := date_trunc('day', input_expr_timestamp);
+                    days_offset := (7 + v_day - datefirst_value)%7;
+                    result_date := result_date - make_interval(days => days_offset);
+            END CASE;
+            -- concat offset_string to result_date in case of datetimeoffset before converting it to datetimeoffset datatype.
+            IF date_arg_datatype = 'sys.datetimeoffset'::regtype THEN
+                RETURN concat(result_date, ' ', offset_string)::sys.datetimeoffset;
+            ELSE
+                RETURN result_date;
+            END IF;
+        END IF;
+    END;
+END;
+$body$
+LANGUAGE plpgsql STABLE;
+
+-- another definition of datetrunc as anyelement can not handle unknown type.
+CREATE OR REPLACE FUNCTION sys.DATETRUNC(IN datepart PG_CATALOG.TEXT, IN date PG_CATALOG.TEXT) RETURNS SYS.DATETIME2 AS
+$body$
+DECLARE
+    input_expr_datetime2 sys.datetime2;
+BEGIN
+    IF datepart NOT IN ('year', 'quarter', 'month', 'week', 'tsql_week', 'hour', 'minute', 'second', 'millisecond', 'microsecond', 
+                        'doy', 'day', 'nanosecond', 'tzoffset') THEN
+            RAISE EXCEPTION '''%'' is not a recognized datetrunc option.', datepart;
+    END IF;
+    BEGIN
+    input_expr_datetime2 := cast(date as sys.datetime2);
+    exception
+        WHEN others THEN
+                RAISE USING MESSAGE := 'Conversion failed when converting date and/or time from character string.';
+    END;
+    IF input_expr_datetime2 IS NULL THEN
+        RETURN NULL;
+    ELSE
+        -- input string literal is valid, call the datetrunc function with datetime2 datatype. 
+        RETURN sys.DATETRUNC(datepart, input_expr_datetime2);
+    END IF;
+END;
+$body$
+LANGUAGE plpgsql STABLE;

contrib/babelfishpg_tsql/sql/upgrades/babelfishpg_tsql--3.3.0--3.4.0.sql

@@ -789,6 +789,113 @@ $BODY$
 LANGUAGE plpgsql
 IMMUTABLE;
 
+
+CREATE OR REPLACE FUNCTION sys.DATETRUNC(IN datepart PG_CATALOG.TEXT, IN date ANYELEMENT) RETURNS ANYELEMENT AS
+$body$
+DECLARE
+    days_offset INT;
+    v_day INT;
+    result_date timestamp;
+    input_expr_timestamp timestamp;
+    date_arg_datatype regtype;
+    offset_string PG_CATALOG.TEXT;
+    datefirst_value INT;
+BEGIN
+    BEGIN
+        /* perform input validation */
+        date_arg_datatype := pg_typeof(date);
+        IF datepart NOT IN ('year', 'quarter', 'month', 'week', 'tsql_week', 'hour', 'minute', 'second', 'millisecond', 'microsecond', 
+                            'doy', 'day', 'nanosecond', 'tzoffset') THEN
+            RAISE EXCEPTION '''%'' is not a recognized datetrunc option.', datepart;
+        ELSIF date_arg_datatype NOT IN ('date'::regtype, 'time'::regtype, 'sys.datetime'::regtype, 'sys.datetime2'::regtype,
+                                        'sys.datetimeoffset'::regtype, 'sys.smalldatetime'::regtype) THEN
+            RAISE EXCEPTION 'Argument data type ''%'' is invalid for argument 2 of datetrunc function.', date_arg_datatype;
+        ELSIF datepart IN ('nanosecond', 'tzoffset') THEN
+            RAISE EXCEPTION 'The datepart ''%'' is not supported by date function datetrunc for data type ''%''.',datepart, date_arg_datatype;
+        ELSIF datepart IN ('dow') THEN
+            RAISE EXCEPTION 'The datepart ''weekday'' is not supported by date function datetrunc for data type ''%''.', date_arg_datatype;
+        ELSIF date_arg_datatype = 'date'::regtype AND datepart IN ('hour', 'minute', 'second', 'millisecond', 'microsecond') THEN
+            RAISE EXCEPTION 'The datepart ''%'' is not supported by date function datetrunc for data type ''date''.', datepart;
+        ELSIF date_arg_datatype = 'datetime'::regtype AND datepart IN ('microsecond') THEN
+            RAISE EXCEPTION 'The datepart ''%'' is not supported by date function datetrunc for data type ''datetime''.', datepart;
+        ELSIF date_arg_datatype = 'smalldatetime'::regtype AND datepart IN ('millisecond', 'microsecond') THEN
+            RAISE EXCEPTION 'The datepart ''%'' is not supported by date function datetrunc for data type ''smalldatetime''.', datepart;
+        ELSIF date_arg_datatype = 'time'::regtype THEN
+            IF datepart IN ('year', 'quarter', 'month', 'doy', 'day', 'week', 'tsql_week') THEN
+                RAISE EXCEPTION 'The datepart ''%'' is not supported by date function datetrunc for data type ''time''.', datepart;
+            END IF;
+            -- Limitation in determining if the specified fractional scale (if provided any) for time datatype is 
+            -- insufficient to support provided datepart (millisecond, microsecond) value
+        ELSIF date_arg_datatype IN ('datetime2'::regtype, 'datetimeoffset'::regtype) THEN
+            -- Limitation in determining if the specified fractional scale (if provided any) for the above datatype is
+            -- insufficient to support for provided datepart (millisecond, microsecond) value
+        END IF;
+
+        /* input validation is complete, proceed with result calculation. */
+        IF date_arg_datatype = 'time'::regtype THEN
+            RETURN date_trunc(datepart, date);
+        ELSE
+            input_expr_timestamp = date::timestamp;
+            -- preserving offset_string value in the case of datetimeoffset datatype before converting it to timestamps 
+            IF date_arg_datatype = 'sys.datetimeoffset'::regtype THEN
+                offset_string = RIGHT(date::PG_CATALOG.TEXT, 6);
+                input_expr_timestamp := LEFT(date::PG_CATALOG.TEXT, -6)::timestamp;
+            END IF;
+            CASE
+                WHEN datepart IN ('year', 'quarter', 'month', 'week', 'hour', 'minute', 'second', 'millisecond', 'microsecond')  THEN
+                    result_date := date_trunc(datepart, input_expr_timestamp);
+                WHEN datepart IN ('doy', 'day') THEN
+                    result_date := date_trunc('day', input_expr_timestamp);
+                WHEN datepart IN ('tsql_week') THEN
+                -- sql server datepart 'iso_week' is similar to postgres 'week' datepart
+                -- handle sql server datepart 'week' here based on the value of set variable 'DATEFIRST'
+                    v_day := EXTRACT(dow from input_expr_timestamp)::INT;
+                    datefirst_value := current_setting('babelfishpg_tsql.datefirst')::INT;
+                    IF v_day = 0 THEN
+                        v_day := 7;
+                    END IF;
+                    result_date := date_trunc('day', input_expr_timestamp);
+                    days_offset := (7 + v_day - datefirst_value)%7;
+                    result_date := result_date - make_interval(days => days_offset);
+            END CASE;
+            -- concat offset_string to result_date in case of datetimeoffset before converting it to datetimeoffset datatype.
+            IF date_arg_datatype = 'sys.datetimeoffset'::regtype THEN
+                RETURN concat(result_date, ' ', offset_string)::sys.datetimeoffset;
+            ELSE
+                RETURN result_date;
+            END IF;
+        END IF;
+    END;
+END;
+$body$
+LANGUAGE plpgsql STABLE;
+
+-- another definition of datetrunc as anyelement can not handle unknown type.
+CREATE OR REPLACE FUNCTION sys.DATETRUNC(IN datepart PG_CATALOG.TEXT, IN date PG_CATALOG.TEXT) RETURNS SYS.DATETIME2 AS
+$body$
+DECLARE
+    input_expr_datetime2 sys.datetime2;
+BEGIN
+    IF datepart NOT IN ('year', 'quarter', 'month', 'week', 'tsql_week', 'hour', 'minute', 'second', 'millisecond', 'microsecond', 
+                        'doy', 'day', 'nanosecond', 'tzoffset') THEN
+            RAISE EXCEPTION '''%'' is not a recognized datetrunc option.', datepart;
+    END IF;
+    BEGIN
+    input_expr_datetime2 := cast(date as sys.datetime2);
+    exception
+        WHEN others THEN
+                RAISE USING MESSAGE := 'Conversion failed when converting date and/or time from character string.';
+    END;
+    IF input_expr_datetime2 IS NULL THEN
+        RETURN NULL;
+    ELSE
+        -- input string literal is valid, call the datetrunc function with datetime2 datatype. 
+        RETURN sys.DATETRUNC(datepart, input_expr_datetime2);
+    END IF;
+END;
+$body$
+LANGUAGE plpgsql STABLE;
+
 -- BABELFISH_SCHEMA_PERMISSIONS
 CREATE TABLE IF NOT EXISTS sys.babelfish_schema_permissions (
   dbid smallint NOT NULL,

contrib/babelfishpg_tsql/src/backend_parser/gram-tsql-decl.y

@@ -96,7 +96,7 @@
 
 %token <keyword> TSQL_ATAT TSQL_ALLOW_SNAPSHOT_ISOLATION
 	TSQL_CALLER TSQL_CHOOSE TSQL_CLUSTERED TSQL_COLUMNSTORE TSQL_CONVERT
-	TSQL_DATENAME TSQL_DATEPART TSQL_DATEDIFF TSQL_DATEDIFF_BIG TSQL_DATE_BUCKET TSQL_DATEADD TSQL_DEFAULT_SCHEMA TSQL_ISNULL
+	TSQL_DATENAME TSQL_DATEPART TSQL_DATETRUNC TSQL_DATEDIFF TSQL_DATEDIFF_BIG TSQL_DATE_BUCKET TSQL_DATEADD TSQL_DEFAULT_SCHEMA TSQL_ISNULL
 	TSQL_D TSQL_DAYOFYEAR TSQL_DD TSQL_DW TSQL_DY TSQL_HH TSQL_ISO_WEEK TSQL_ISOWK
 	TSQL_ISOWW TSQL_LOGIN TSQL_M TSQL_MCS TSQL_MI TSQL_MICROSECOND TSQL_MILLISECOND TSQL_MM TSQL_MS
 	TSQL_N TSQL_NANOSECOND TSQL_NONCLUSTERED TSQL_NS TSQL_OUTPUT TSQL_OUT TSQL_PARSE TSQL_Q

contrib/babelfishpg_tsql/src/backend_parser/gram-tsql-rule.y

@@ -1936,6 +1936,13 @@ func_expr_common_subexpr:
 											   COERCE_EXPLICIT_CALL,
 											   @1);
 				}
+			| TSQL_DATETRUNC '(' datepart_arg ',' a_expr ')'
+				{
+					$$ = (Node *) makeFuncCall(TsqlSystemFuncName2("datetrunc"),
+												list_make2(makeStringConst($3, @3), $5),
+												COERCE_EXPLICIT_CALL,
+												@1);
+				}
 			| TSQL_DATENAME '(' datepart_arg ',' a_expr ')'
 				{
 					$$ = (Node *) makeFuncCall(TsqlSystemFuncName2("datename"),
@@ -4465,6 +4472,7 @@ reserved_keyword:
 			| TSQL_DATE_BUCKET
 			| TSQL_DATENAME
 			| TSQL_DATEPART
+			| TSQL_DATETRUNC
 			| TSQL_IIF
 			| TSQL_OUT
 			| TSQL_OUTER

contrib/babelfishpg_tsql/src/backend_parser/kwlist.h

@@ -116,6 +116,7 @@ PG_KEYWORD("datediff", TSQL_DATEDIFF, RESERVED_KEYWORD)
 PG_KEYWORD("datediff_big", TSQL_DATEDIFF_BIG, RESERVED_KEYWORD)
 PG_KEYWORD("datename", TSQL_DATENAME, RESERVED_KEYWORD)
 PG_KEYWORD("datepart", TSQL_DATEPART, RESERVED_KEYWORD)
+PG_KEYWORD("datetrunc", TSQL_DATETRUNC, RESERVED_KEYWORD)
 PG_KEYWORD("day", DAY_P, UNRESERVED_KEYWORD)
 PG_KEYWORD("dayofyear", TSQL_DAYOFYEAR, UNRESERVED_KEYWORD)
 PG_KEYWORD("dd", TSQL_DD, UNRESERVED_KEYWORD)

contrib/babelfishpg_tsql/src/backend_parser/scan-tsql-rule.l

@@ -218,6 +218,7 @@
 							case TSQL_DATE_BUCKET:
 							case TSQL_DATENAME:
 							case TSQL_DATEPART:
+							case TSQL_DATETRUNC:
 							case TSQL_D:
 							case TSQL_DAYOFYEAR:
 							case TSQL_DD:

contrib/babelfishpg_tsql/src/special_keywords.c

@@ -89,6 +89,7 @@ const char *pg_reserved_keywords_to_be_delimited[] = {
 	"date_bucket",
 	"datename",
 	"datepart",
+	"datetrunc",
 	"iif",
 	"out",
 	"output",

test/JDBC/expected/BABEL-3953-datetrunc-vu-cleanup.out

@@ -0,0 +1,59 @@
+DROP VIEW DATETRUNC_vu_prepare_v1
+GO
+
+DROP VIEW DATETRUNC_vu_prepare_v2
+GO
+
+DROP VIEW DATETRUNC_vu_prepare_v3
+GO
+
+DROP VIEW DATETRUNC_vu_prepare_v4
+GO
+
+DROP VIEW DATETRUNC_vu_prepare_v5
+GO
+
+DROP VIEW DATETRUNC_vu_prepare_v6
+GO
+
+DROP VIEW DATETRUNC_vu_prepare_v7
+GO
+
+DROP VIEW DATETRUNC_vu_prepare_v8
+GO
+
+DROP VIEW DATETRUNC_vu_prepare_v9
+GO
+
+DROP VIEW DATETRUNC_vu_prepare_v10
+GO
+
+DROP VIEW DATETRUNC_vu_prepare_v11
+GO
+
+DROP PROCEDURE BABEL_3953_vu_prepare_p1
+GO
+
+DROP PROCEDURE BABEL_3953_vu_prepare_p2
+GO
+
+DROP PROCEDURE BABEL_3953_vu_prepare_p3
+GO
+
+DROP PROCEDURE BABEL_3953_vu_prepare_p4
+GO
+
+DROP PROCEDURE BABEL_3953_vu_prepare_p5
+GO
+
+DROP PROCEDURE BABEL_3953_vu_prepare_p6
+GO
+
+DROP FUNCTION BABEL_3953_vu_prepare_f1
+GO
+
+DROP FUNCTION BABEL_3953_vu_prepare_f2
+GO
+
+DROP FUNCTION BABEL_3953_vu_prepare_f3
+GO