SQL: regression fix: make NOW a valid identifier again [#363]

* again, as in 10.2, NOW is a keyword only if followed by parentheses
* use AS OF CURRENT_TIMESTAMP or AS OF NOW()
* AS OF CURRENT_TIMESTAMP and AS OF NOW() mean AS OF NOW(6),
  not AS OF NOW(0), (same behavior as in a DEFAULT clause)

12 files changed, 79 insertions, 66 deletions

diff --git a/mysql-test/r/parser.result b/mysql-test/r/parser.result
index c57e2c2c803..f197fbe6a19 100644
--- a/mysql-test/r/parser.result
+++ b/mysql-test/r/parser.result
@@ -64,8 +64,10 @@ create table MIN(a int);
 ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'MIN(a int)' at line 1
 create table MIN (a int);
 drop table MIN;
+create table NOW(a int);
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'NOW(a int)' at line 1
 create table NOW (a int);
-ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'NOW (a int)' at line 1
+drop table NOW;
 create table POSITION(a int);
 ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'POSITION(a int)' at line 1
 create table POSITION (a int);
diff --git a/mysql-test/suite/versioning/r/cte.result b/mysql-test/suite/versioning/r/cte.result
index 12532041857..20fe0c1a081 100644
--- a/mysql-test/suite/versioning/r/cte.result
+++ b/mysql-test/suite/versioning/r/cte.result
@@ -42,7 +42,7 @@ from emp for system_time as of timestamp @ts_1 as e,
 ancestors as a
 where e.mgr = a.emp_id
 )
-select * from ancestors for system_time as of now;
+select * from ancestors for system_time as of current_timestamp;
 emp_id	name	mgr	salary
 1	bill	NULL	1000
 30	jane	1	750
diff --git a/mysql-test/suite/versioning/r/derived.result b/mysql-test/suite/versioning/r/derived.result
index 9f110ba0c29..d2a909ebf44 100644
--- a/mysql-test/suite/versioning/r/derived.result
+++ b/mysql-test/suite/versioning/r/derived.result
@@ -152,13 +152,13 @@ y	x
 with s3 as (select *, t1.sys_trx_end from t2, t1 for system_time as of timestamp @t0) select * from s3;
 y	x
 10	1
-select * from (select *, t1.sys_trx_start from t2 for system_time as of now, t1) as s4 for system_time as of timestamp @t0;
+select * from (select *, t1.sys_trx_start from t2 for system_time as of current_timestamp, t1) as s4 for system_time as of timestamp @t0;
 y	x
 10	1
-with s5 as (select *, t1.sys_trx_start from t2 for system_time as of now, t1) select * from s5 for system_time as of timestamp @t0;
+with s5 as (select *, t1.sys_trx_start from t2 for system_time as of current_timestamp, t1) select * from s5 for system_time as of timestamp @t0;
 y	x
 10	1
-with s6 as (select *, t1.sys_trx_start from t2 for system_time as of now, t1) select * from s6 for system_time as of timestamp @t0;
+with s6 as (select *, t1.sys_trx_start from t2 for system_time as of current_timestamp, t1) select * from s6 for system_time as of timestamp @t0;
 y	x
 10	1
 set @q= concat("create view vt1 as select * from t1 for system_time as of timestamp '", @t0, "'");
@@ -174,7 +174,7 @@ x	y
 select * from (select *, vt1.sys_trx_end from t2, vt1) as s0;
 y	x
 10	1
-select * from (select *, vt1.sys_trx_start from t2 for system_time as of now, vt1) as s0 for system_time as of timestamp @t0;
+select * from (select *, vt1.sys_trx_start from t2 for system_time as of current_timestamp, vt1) as s0 for system_time as of timestamp @t0;
 y	x
 10	1
 drop table t1, t2;
diff --git a/mysql-test/suite/versioning/r/partition.result b/mysql-test/suite/versioning/r/partition.result
index 3c6445eeb8d..58ac879c3e2 100644
--- a/mysql-test/suite/versioning/r/partition.result
+++ b/mysql-test/suite/versioning/r/partition.result
@@ -30,24 +30,24 @@ x
 create or replace table t1 (x int)
 partition by system_time (
 partition p0 versioning,
-partition pn as of now);
+partition pn as of current_timestamp);
 ERROR HY000: System Versioning required: t1
 create or replace table t1 (x int);
 alter table t1
 partition by system_time (
 partition p0 versioning,
-partition pn as of now);
+partition pn as of current_timestamp);
 Got one of the listed errors
 create or replace table t1 (x int)
 with system versioning
 partition by system_time (
-partition p0 as of now);
+partition p0 as of current_timestamp);
 ERROR HY000: Wrong partitions consistency for `t1`: must have at least one 'VERSIONING' and exactly one last 'AS OF NOW'
 create or replace table t1 (x int)
 with system versioning
 partition by system_time (
-partition p0 as of now,
-partition p1 as of now);
+partition p0 as of current_timestamp,
+partition p1 as of current_timestamp);
 ERROR HY000: Wrong partitions consistency for `t1`: must have at least one 'VERSIONING' and exactly one last 'AS OF NOW'
 create or replace table t1 (x int)
 with system versioning
@@ -58,16 +58,16 @@ ERROR HY000: Wrong partitions consistency for `t1`: must have at least one 'VERS
 create or replace table t1 (x int)
 with system versioning
 partition by system_time (
-partition pn as of now,
+partition pn as of current_timestamp,
 partition p0 versioning);
 ERROR HY000: Wrong partitions consistency for `t1`: must have at least one 'VERSIONING' and exactly one last 'AS OF NOW'
 create or replace table t1 (x int)
 with system versioning
 partition by system_time (
 partition p0 versioning,
-partition pn as of now);
+partition pn as of current_timestamp);
 alter table t1 add partition (
-partition p1 as of now);
+partition p1 as of current_timestamp);
 ERROR HY000: Wrong partitions consistency for `t1`: must have at least one 'VERSIONING' and exactly one last 'AS OF NOW'
 alter table t1 add partition (
 partition p1 versioning);
@@ -84,7 +84,7 @@ t1	CREATE TABLE `t1` (
  PARTITION BY SYSTEM_TIME 
 (PARTITION `p0` VERSIONING ENGINE = ${INNODB_OR_MYISAM},
  PARTITION `p1` VERSIONING ENGINE = ${INNODB_OR_MYISAM},
- PARTITION `pn` AS OF NOW ENGINE = ${INNODB_OR_MYISAM})
+ PARTITION `pn` AS OF CURRENT_TIMESTAMP ENGINE = ${INNODB_OR_MYISAM})
 insert into t1 values (1), (2);
 alter table t1 drop partition pn;
 ERROR HY000: Wrong partitions consistency for `t1`: must have at least one 'VERSIONING' and exactly one last 'AS OF NOW'
@@ -99,7 +99,7 @@ create or replace table t1 (x int)
 with system versioning
 partition by system_time (
 partition p0 versioning,
-partition pn as of now);
+partition pn as of current_timestamp);
 set @now= now(6);
 insert into t1 values (1);
 set @ts_start= sys_commit_ts('sys_trx_start');
@@ -180,14 +180,14 @@ with system versioning
 partition by system_time limit 0 (
 partition p0 versioning,
 partition p1 versioning,
-partition pn as of now);
+partition pn as of current_timestamp);
 ERROR HY000: Wrong parameters for partitioned `t1`: wrong value for 'LIMIT'
 create or replace table t1 (x int)
 with system versioning
 partition by system_time limit 1 (
 partition p0 versioning,
 partition p1 versioning,
-partition pn as of now);
+partition pn as of current_timestamp);
 show create table t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
@@ -199,7 +199,7 @@ t1	CREATE TABLE `t1` (
  PARTITION BY SYSTEM_TIME LIMIT 1
 (PARTITION `p0` VERSIONING ENGINE = ${INNODB_OR_MYISAM},
  PARTITION `p1` VERSIONING ENGINE = ${INNODB_OR_MYISAM},
- PARTITION `pn` AS OF NOW ENGINE = ${INNODB_OR_MYISAM})
+ PARTITION `pn` AS OF CURRENT_TIMESTAMP ENGINE = ${INNODB_OR_MYISAM})
 alter table t1 drop partition non_existent;
 ERROR HY000: Error in list of partitions to DROP
 insert into t1 values (1), (2);
@@ -229,14 +229,14 @@ with system versioning
 partition by system_time interval 0 second (
 partition p0 versioning,
 partition p1 versioning,
-partition pn as of now);
+partition pn as of current_timestamp);
 ERROR HY000: Wrong parameters for partitioned `t1`: wrong value for 'INTERVAL'
 create or replace table t1 (x int)
 with system versioning
 partition by system_time interval 1 second (
 partition p0 versioning,
 partition p1 versioning,
-partition pn as of now);
+partition pn as of current_timestamp);
 insert into t1 values (1), (2), (3);
 select * from t1 partition (pn);
 x
@@ -263,7 +263,7 @@ subpartition by key (x)
 subpartitions 2 (
 partition p0 versioning,
 partition p1 versioning,
-partition pn as of now);
+partition pn as of current_timestamp);
 insert into t1 (x) values (1), (2), (3);
 select * from t1 partition (pnsp0);
 x
diff --git a/mysql-test/suite/versioning/t/cte.test b/mysql-test/suite/versioning/t/cte.test
index 084b4feec57..bc7caec9e71 100644
--- a/mysql-test/suite/versioning/t/cte.test
+++ b/mysql-test/suite/versioning/t/cte.test
@@ -49,7 +49,7 @@ as
        ancestors as a
   where e.mgr = a.emp_id
 )
-select * from ancestors for system_time as of now;
+select * from ancestors for system_time as of current_timestamp;
 
 /* Expected 3 rows */
 with recursive
diff --git a/mysql-test/suite/versioning/t/derived.test b/mysql-test/suite/versioning/t/derived.test
index 35abebb7743..9e3bd367064 100644
--- a/mysql-test/suite/versioning/t/derived.test
+++ b/mysql-test/suite/versioning/t/derived.test
@@ -112,9 +112,9 @@ with s1 as (select * from t1 for system_time as of timestamp @t0, t2) select * f
 select * from (select *, t1.sys_trx_end from t2, t1 for system_time as of timestamp @t0) as s2;
 with s3 as (select *, t1.sys_trx_end from t2, t1 for system_time as of timestamp @t0) select * from s3;
 # system_time propagation from outer to inner
-select * from (select *, t1.sys_trx_start from t2 for system_time as of now, t1) as s4 for system_time as of timestamp @t0;
-with s5 as (select *, t1.sys_trx_start from t2 for system_time as of now, t1) select * from s5 for system_time as of timestamp @t0;
-with s6 as (select *, t1.sys_trx_start from t2 for system_time as of now, t1) select * from s6 for system_time as of timestamp @t0;
+select * from (select *, t1.sys_trx_start from t2 for system_time as of current_timestamp, t1) as s4 for system_time as of timestamp @t0;
+with s5 as (select *, t1.sys_trx_start from t2 for system_time as of current_timestamp, t1) select * from s5 for system_time as of timestamp @t0;
+with s6 as (select *, t1.sys_trx_start from t2 for system_time as of current_timestamp, t1) select * from s6 for system_time as of timestamp @t0;
 
 # VIEW instead of t1
 set @q= concat("create view vt1 as select * from t1 for system_time as of timestamp '", @t0, "'");
@@ -127,7 +127,7 @@ select * from (select * from vt1, t2) as s0;
 # leading table selection
 select * from (select *, vt1.sys_trx_end from t2, vt1) as s0;
 # system_time propagation from outer to inner
-select * from (select *, vt1.sys_trx_start from t2 for system_time as of now, vt1) as s0 for system_time as of timestamp @t0;
+select * from (select *, vt1.sys_trx_start from t2 for system_time as of current_timestamp, vt1) as s0 for system_time as of timestamp @t0;
 
 drop table t1, t2;
 drop view vt1;
diff --git a/mysql-test/suite/versioning/t/partition.test b/mysql-test/suite/versioning/t/partition.test
index cbc02d44e31..7abaf591a4e 100644
--- a/mysql-test/suite/versioning/t/partition.test
+++ b/mysql-test/suite/versioning/t/partition.test
@@ -26,27 +26,27 @@ select * from t1 partition (p1) for system_time all;
 create or replace table t1 (x int)
 partition by system_time (
     partition p0 versioning,
-    partition pn as of now);
+    partition pn as of current_timestamp);
 
 create or replace table t1 (x int);
 --error ER_VERSIONING_REQUIRED,ER_VERSIONING_REQUIRED
 alter table t1
 partition by system_time (
     partition p0 versioning,
-    partition pn as of now);
+    partition pn as of current_timestamp);
 
 --error ER_VERS_WRONG_PARTS
 create or replace table t1 (x int)
 with system versioning
 partition by system_time (
-    partition p0 as of now);
+    partition p0 as of current_timestamp);
 
 --error ER_VERS_WRONG_PARTS
 create or replace table t1 (x int)
 with system versioning
 partition by system_time (
-    partition p0 as of now,
-    partition p1 as of now);
+    partition p0 as of current_timestamp,
+    partition p1 as of current_timestamp);
 
 --error ER_VERS_WRONG_PARTS
 create or replace table t1 (x int)
@@ -59,19 +59,19 @@ partition by system_time (
 create or replace table t1 (x int)
 with system versioning
 partition by system_time (
-    partition pn as of now,
+    partition pn as of current_timestamp,
     partition p0 versioning);
 
 create or replace table t1 (x int)
 with system versioning
 partition by system_time (
     partition p0 versioning,
-    partition pn as of now);
+    partition pn as of current_timestamp);
 
 # alter table
 --error ER_VERS_WRONG_PARTS
 alter table t1 add partition (
-    partition p1 as of now);
+    partition p1 as of current_timestamp);
 
 alter table t1 add partition (
     partition p1 versioning);
@@ -94,7 +94,7 @@ create or replace table t1 (x int)
 with system versioning
 partition by system_time (
     partition p0 versioning,
-    partition pn as of now);
+    partition pn as of current_timestamp);
 
 set @now= now(6);
 insert into t1 values (1);
@@ -158,14 +158,14 @@ with system versioning
 partition by system_time limit 0 (
     partition p0 versioning,
     partition p1 versioning,
-    partition pn as of now);
+    partition pn as of current_timestamp);
 
 create or replace table t1 (x int)
 with system versioning
 partition by system_time limit 1 (
     partition p0 versioning,
     partition p1 versioning,
-    partition pn as of now);
+    partition pn as of current_timestamp);
 
 --replace_result InnoDB ${INNODB_OR_MYISAM} MyISAM ${INNODB_OR_MYISAM} "bigint(20) unsigned" ${SYS_TRX_TYPE} timestamp(6) ${SYS_TRX_TYPE}
 show create table t1;
@@ -190,14 +190,14 @@ with system versioning
 partition by system_time interval 0 second (
     partition p0 versioning,
     partition p1 versioning,
-    partition pn as of now);
+    partition pn as of current_timestamp);
 
 create or replace table t1 (x int)
 with system versioning
 partition by system_time interval 1 second (
     partition p0 versioning,
     partition p1 versioning,
-    partition pn as of now);
+    partition pn as of current_timestamp);
 
 insert into t1 values (1), (2), (3);
 select * from t1 partition (pn);
@@ -217,7 +217,7 @@ subpartition by key (x)
 subpartitions 2 (
     partition p0 versioning,
     partition p1 versioning,
-    partition pn as of now);
+    partition pn as of current_timestamp);
 
 insert into t1 (x) values (1), (2), (3);
 select * from t1 partition (pnsp0);
diff --git a/mysql-test/t/parser.test b/mysql-test/t/parser.test
index 3be42eb0595..98eaa7a7774 100644
--- a/mysql-test/t/parser.test
+++ b/mysql-test/t/parser.test
@@ -104,7 +104,9 @@ create table MIN (a int);
 drop table MIN;
 
 --error ER_PARSE_ERROR
+create table NOW(a int);
 create table NOW (a int);
+drop table NOW;
 
 --error ER_PARSE_ERROR
 create table POSITION(a int);
diff --git a/sql/lex.h b/sql/lex.h
index f0ee16dea57..25b6b834a55 100644
--- a/sql/lex.h
+++ b/sql/lex.h
@@ -428,7 +428,6 @@ static SYMBOL symbols[] = {
   { "NONE",		SYM(NONE_SYM)},
   { "NOT",		SYM(NOT_SYM)},
   { "NOTFOUND",         SYM(NOTFOUND_SYM)},
-  { "NOW",		SYM(NOW_SYM)},
   { "NO_WRITE_TO_BINLOG",  SYM(NO_WRITE_TO_BINLOG)},
   { "NULL",		SYM(NULL_SYM)},
   { "NUMBER",           SYM(NUMBER_SYM)},
@@ -746,6 +745,7 @@ static SYMBOL sql_functions[] = {
   { "MEDIAN", SYM(MEDIAN_SYM)},
   { "MID",		SYM(SUBSTRING)},	/* unireg function */
   { "MIN",		SYM(MIN_SYM)},
+  { "NOW",		SYM(NOW_SYM)},
   { "NTH_VALUE",        SYM(NTH_VALUE_SYM)},
   { "NTILE",            SYM(NTILE_SYM)},
   { "POSITION",		SYM(POSITION_SYM)},
diff --git a/sql/sql_partition.cc b/sql/sql_partition.cc
index 700b25419e8..55d906bb3b4 100644
--- a/sql/sql_partition.cc
+++ b/sql/sql_partition.cc
@@ -2221,7 +2221,7 @@ static int add_partition_values(String *str, partition_info *part_info,
     switch (p_elem->type())
     {
     case partition_element::AS_OF_NOW:
-      err+= str->append(STRING_WITH_LEN(" AS OF NOW"));
+      err+= str->append(STRING_WITH_LEN(" AS OF CURRENT_TIMESTAMP"));
       break;
     case partition_element::VERSIONING:
       err+= str->append(STRING_WITH_LEN(" VERSIONING"));
diff --git a/sql/sql_yacc.yy b/sql/sql_yacc.yy
index 41d0070ddfd..47400338a31 100644
--- a/sql/sql_yacc.yy
+++ b/sql/sql_yacc.yy
@@ -739,6 +739,32 @@ bool LEX::set_bincmp(CHARSET_INFO *cs, bool bin)
        MYSQL_YYABORT;                   \
   } while(0)
 
+
+inline void vers_select_conds_t::init(
+    vers_range_type_t t,
+    vers_range_unit_t u_start= UNIT_AUTO,
+    Item * s= NULL,
+    vers_range_unit_t u_end= UNIT_AUTO,
+    Item * e= NULL)
+{
+  type= t;
+  unit_start= u_start;
+  unit_end= u_end;
+  start= fix_dec(s);
+  end= fix_dec(e);
+  import_outer= from_inner= false;
+}
+
+inline Item *vers_select_conds_t::fix_dec(Item *item)
+{
+  if (item && item->decimals == 0 && item->type() == Item::FUNC_ITEM &&
+      ((Item_func*)item)->functype() == Item_func::NOW_FUNC)
+    item->decimals= 6;
+
+  return item;
+}
+
+
 Virtual_column_info *add_virtual_expression(THD *thd, Item *expr)
 {
   Virtual_column_info *v= new (thd->mem_root) Virtual_column_info();
@@ -870,10 +896,10 @@ bool my_yyoverflow(short **a, YYSTYPE **b, ulong *yystacksize);
 %parse-param { THD *thd }
 %lex-param { THD *thd }
 /*
-  Currently there are 124 shift/reduce conflicts.
+  Currently there are 123 shift/reduce conflicts.
   We should not introduce new conflicts any more.
 */
-%expect 124
+%expect 123
 
 /*
    Comments for TOKENS.
@@ -9032,13 +9058,6 @@ system_time_expr:
           {
             Lex->vers_conditions.init(FOR_SYSTEM_TIME_AS_OF, $3, $4);
           }
-        | AS OF_SYM NOW_SYM
-          {
-            Item *item= new (thd->mem_root) Item_func_now_local(thd, 6);
-            if (item == NULL)
-              MYSQL_YYABORT;
-            Lex->vers_conditions.init(FOR_SYSTEM_TIME_AS_OF, UNIT_TIMESTAMP, item);
-          }
         | ALL
           {
             Lex->vers_conditions.init(FOR_SYSTEM_TIME_ALL);
diff --git a/sql/table.h b/sql/table.h
index 869469f18a0..55218837510 100644
--- a/sql/table.h
+++ b/sql/table.h
@@ -1871,20 +1871,10 @@ struct vers_select_conds_t
     start= end= NULL;
   }
 
-  void init(
-    vers_range_type_t t,
-    vers_range_unit_t u_start= UNIT_AUTO,
-    Item * s= NULL,
-    vers_range_unit_t u_end= UNIT_AUTO,
-    Item * e= NULL)
-  {
-    type= t;
-    unit_start= u_start;
-    unit_end= u_end;
-    start= s;
-    end= e;
-    import_outer= from_inner= false;
-  }
+  inline Item *fix_dec(Item *item);
+
+  inline void init( vers_range_type_t t, vers_range_unit_t u_start,
+    Item * s, vers_range_unit_t u_end, Item * e);
 
   bool init_from_sysvar(THD *thd);