add support for to_timestamp

src/adjust.c

@@ -93,6 +93,7 @@ CustomObjectDef *chfdw_check_for_custom_function(Oid funcid)
 			case 868: // strpos
 			case F_BTRIM:
 			case F_BTRIM1:
+			case F_TO_TIMESTAMP:
 				special_builtin = true;
 				break;
 			default:
@@ -153,6 +154,12 @@ CustomObjectDef *chfdw_check_for_custom_function(Oid funcid)
 				strcpy(entry->custom_name, "position");
 				break;
 			}
+			case F_TO_TIMESTAMP:
+			{
+				entry->cf_type = CF_TO_TIMESTAMP;
+				entry->custom_name[0] = '\1';
+				break;
+			}
 		}
 
 		if (special_builtin)

src/deparse.c

@@ -2359,6 +2359,16 @@ deparseFuncExpr(FuncExpr *node, deparse_expr_cxt *context)
 	 * Normal function: display as proname(args).
 	 */
 	cdef = appendFunctionName(node->funcid, context);
+
+	if (cdef && cdef->cf_type == CF_TO_TIMESTAMP)
+	{
+		appendStringInfoString(buf, "parseDateTimeBestEffortOrNull");
+		appendStringInfoChar(buf, '(');
+		deparseExpr(list_nth(node->args, 0), context);
+		appendStringInfoChar(buf, ')');
+		return;
+	}
+
 	if (cdef && cdef->cf_type == CF_DATE_TRUNC)
 	{
 		Const *arg = (Const *) linitial(node->args);
@@ -2409,7 +2419,7 @@ deparseFuncExpr(FuncExpr *node, deparse_expr_cxt *context)
 		{
 			appendStringInfoString(buf, "(toDateTime64(");
 			deparseExpr(list_nth(node->args, 1), context);
-			appendStringInfoString(buf, ", 1))");
+			appendStringInfoString(buf, ", 1, 'UTC'))");
 		}
 		else
 		{

src/include/clickhousedb_fdw.h

@@ -268,6 +268,7 @@ typedef enum {
 	CF_DATE_PART,		/* date_part function */
 	CF_TIMESTAMPTZ_PL_INTERVAL,	/* timestamptz + interval */
 	CF_TIMEZONE,		/* timezone */
+	CF_TO_TIMESTAMP,
 	CF_COUNTRY_TYPE,
 	CF_AJTIME_PL_INTERVAL,
 	CF_AJTIME_MI_INTERVAL,

tests/expected/functions.out

@@ -233,6 +233,22 @@ SELECT uniq_exact(a) FILTER(WHERE b>1) FROM t1;
           1
 (1 row)
 
+EXPLAIN (VERBOSE, COSTS OFF) SELECT c as d1 FROM t1 WHERE c >= to_timestamp('2019-01-01 00:00:00.000000', 'YYYY-MM-DD HH24:MI:SS.US') GROUP BY d1 ORDER BY d1;
+                                                                                QUERY PLAN                                                                                
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: c
+   Relations: Aggregate on (t1)
+   Remote SQL: SELECT c FROM regression.t1 WHERE ((c >= parseDateTimeBestEffortOrNull('2019-01-01 00:00:00.000000'))) GROUP BY c ORDER BY c ASC
+(4 rows)
+
+SELECT c as d1 FROM t1 WHERE c >= to_timestamp('2019-01-01 00:00:00.000000', 'YYYY-MM-DD HH24:MI:SS.US') GROUP BY d1 ORDER BY d1;
+           d1           
+------------------------
+ 2019-01-01 10:00:00
+ 2019-01-02 10:00:00
+(2 rows)
+
 EXPLAIN (VERBOSE, COSTS OFF) SELECT date_trunc('dAy', c at time zone 'UTC') as d1 FROM t1 GROUP BY d1 ORDER BY d1;
                                                                                 QUERY PLAN                                                                                
 --------------------------------------------------------------------------------------------------------------------------------------------------------------------------

tests/sql/functions.sql

@@ -78,6 +78,9 @@ SELECT uniq_exact(a) FROM t1;
 EXPLAIN (VERBOSE, COSTS OFF) SELECT uniq_exact(a) FILTER(WHERE b>1) FROM t1;
 SELECT uniq_exact(a) FILTER(WHERE b>1) FROM t1;
 
+EXPLAIN (VERBOSE, COSTS OFF) SELECT c as d1 FROM t1 WHERE c >= to_timestamp('2019-01-01 00:00:00.000000', 'YYYY-MM-DD HH24:MI:SS.US') GROUP BY d1 ORDER BY d1;
+SELECT c as d1 FROM t1 WHERE c >= to_timestamp('2019-01-01 00:00:00.000000', 'YYYY-MM-DD HH24:MI:SS.US') GROUP BY d1 ORDER BY d1;
+
 EXPLAIN (VERBOSE, COSTS OFF) SELECT date_trunc('dAy', c at time zone 'UTC') as d1 FROM t1 GROUP BY d1 ORDER BY d1;
 SELECT date_trunc('day', c at time zone 'UTC') as d1 FROM t1 GROUP BY d1 ORDER BY d1;