MDEV-15378 Valid query causes invalid view definition due to syntax limitation in FOR SYSTEM_TIME

fix parsing of the AS OF clause

mysql-test/suite/versioning/r/view.result

@@ -107,7 +107,9 @@ create or replace view vt1 as select * from t1 union select * from t2;
 select * from vt1;
 a
 1
+#
 # MDEV-14689 crash on second PS execute
+#
 create or replace table t1 (a int);
 create or replace view v1 as select * from t1;
 create or replace table t2 (b int) with system versioning;
@@ -119,6 +121,9 @@ a
 drop database test;
 create database test;
 use test;
+#
+# MDEV-15146 SQLError[4122]: View is not system versioned
+#
 create table t1 (a int) with system versioning;
 insert t1 values (1),(2);
 set @a=now(6);
@@ -133,5 +138,15 @@ a
 show create view v1;
 View	Create View	character_set_client	collation_connection
 v1	CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `v1` AS select `t1`.`a` AS `a` from `t1`	latin1	latin1_swedish_ci
+#
+# MDEV-15378 Valid query causes invalid view definition due to syntax limitation in FOR SYSTEM_TIME
+#
+create or replace table t1 (i int) with system versioning;
+select * from t1 for system_time as of now() - interval 6 second;
+i
+create or replace view v1 as select * from t1 for system_time as of date_sub(now(), interval 6 second);
+show create view v1;
+View	Create View	character_set_client	collation_connection
+v1	CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `v1` AS select `t1`.`i` AS `i` from `t1` FOR SYSTEM_TIME AS OF current_timestamp() - interval 6 second	latin1	latin1_swedish_ci
 drop view v1;
 drop table t1;

mysql-test/suite/versioning/t/view.test

@@ -89,7 +89,9 @@ create or replace table t2 (a int);
 create or replace view vt1 as select * from t1 union select * from t2;
 select * from vt1;
 
+--echo #
 --echo # MDEV-14689 crash on second PS execute
+--echo #
 create or replace table t1 (a int);
 create or replace view v1 as select * from t1;
 create or replace table t2 (b int) with system versioning;
@@ -100,10 +102,9 @@ drop database test;
 create database test;
 use test;
 
-#
-# MDEV-15146 SQLError[4122]: View is not system versioned
-#
-
+--echo #
+--echo # MDEV-15146 SQLError[4122]: View is not system versioned
+--echo #
 create table t1 (a int) with system versioning;
 insert t1 values (1),(2);
 set @a=now(6);
@@ -112,5 +113,14 @@ delete from t1;
 select * from v1;
 select * from v1 for system_time as of @a;
 show create view v1;
+
+--echo #
+--echo # MDEV-15378 Valid query causes invalid view definition due to syntax limitation in FOR SYSTEM_TIME
+--echo #
+create or replace table t1 (i int) with system versioning;
+select * from t1 for system_time as of now() - interval 6 second;
+create or replace view v1 as select * from t1 for system_time as of date_sub(now(), interval 6 second);
+show create view v1;
+
 drop view v1;
 drop table t1;

sql/sql_yacc.yy

@@ -9229,7 +9229,7 @@ history_point:
           {
             $$= Vers_history_point(VERS_TIMESTAMP, $1);
           }
-        | opt_history_unit simple_expr
+        | opt_history_unit bit_expr
           {
             $$= Vers_history_point($1, $2);
           }
@@ -9255,13 +9255,11 @@ system_time_expr:
           {
             Lex->vers_conditions.init(SYSTEM_TIME_ALL);
           }
-        | FROM history_point
-          TO_SYM history_point
+        | FROM history_point TO_SYM history_point
           {
             Lex->vers_conditions.init(SYSTEM_TIME_FROM_TO, $2, $4);
           }
-        | BETWEEN_SYM history_point
-          AND_SYM history_point
+        | BETWEEN_SYM history_point AND_SYM history_point
           {
             Lex->vers_conditions.init(SYSTEM_TIME_BETWEEN, $2, $4);
           }