Parser: useful attributes for AS ROW fields

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

@@ -63,16 +63,16 @@ end~~
 drop table if exists t1;
 create table t1 (
 x1 int unsigned,
-Sys_start SYS_TRX_TYPE generated always as row start,
-Sys_end SYS_TRX_TYPE generated always as row end,
+Sys_start SYS_TRX_TYPE generated always as row start comment 'start',
+Sys_end SYS_TRX_TYPE generated always as row end comment 'end',
 period for system_time (Sys_start, Sys_end)
 ) with system versioning;
 show create table t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
   `x1` int(10) unsigned DEFAULT NULL,
-  `Sys_start` SYS_TRX_TYPE GENERATED ALWAYS AS ROW START,
-  `Sys_end` SYS_TRX_TYPE GENERATED ALWAYS AS ROW END,
+  `Sys_start` SYS_TRX_TYPE GENERATED ALWAYS AS ROW START COMMENT 'start',
+  `Sys_end` SYS_TRX_TYPE GENERATED ALWAYS AS ROW END COMMENT 'end',
   PERIOD FOR SYSTEM_TIME (`Sys_start`, `Sys_end`)
 ) ENGINE=INNODB_OR_MYISAM DEFAULT CHARSET=latin1 WITH SYSTEM VERSIONING
 # Implicit fields test

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

@@ -9,8 +9,8 @@ drop table if exists t1;
 --replace_result "bigint unsigned" SYS_TRX_TYPE timestamp(6) SYS_TRX_TYPE
 eval create table t1 (
   x1 int unsigned,
-  Sys_start $sys_datatype generated always as row start,
-  Sys_end $sys_datatype generated always as row end,
+  Sys_start $sys_datatype generated always as row start comment 'start',
+  Sys_end $sys_datatype generated always as row end comment 'end',
   period for system_time (Sys_start, Sys_end)
 ) with system versioning;
 --replace_result InnoDB INNODB_OR_MYISAM MyISAM INNODB_OR_MYISAM "bigint(20) unsigned" SYS_TRX_TYPE timestamp(6) SYS_TRX_TYPE

sql/sql_yacc.yy

@@ -6262,6 +6262,15 @@ opt_serial_attribute_list:
         | serial_attribute
         ;
 
+opt_asrow_attribute:
+          /* empty */ {}
+        | opt_asrow_attribute_list {}
+        ;
+
+opt_asrow_attribute_list:
+          opt_asrow_attribute_list asrow_attribute {}
+        | asrow_attribute
+        ;
 
 field_def:
           opt_attribute
@@ -6271,7 +6280,7 @@ field_def:
            Lex->last_field->flags&= ~NOT_NULL_FLAG; // undo automatic NOT NULL for timestamps
          }
           vcol_opt_specifier vcol_opt_attribute
-        | opt_generated_always AS ROW_SYM start_or_end
+        | opt_generated_always AS ROW_SYM start_or_end opt_asrow_attribute
           {
             LEX *lex= Lex;
             Vers_parse_info &info= lex->vers_get_info();
@@ -6743,7 +6752,7 @@ attribute:
         | serial_attribute
         ;
 
-serial_attribute:
+asrow_attribute:
           not NULL_SYM
           {
             Lex->last_field->flags|= NOT_NULL_FLAG;
@@ -6768,6 +6777,10 @@ serial_attribute:
             lex->alter_info.flags|= Alter_info::ALTER_ADD_INDEX; 
           }
         | COMMENT_SYM TEXT_STRING_sys { Lex->last_field->comment= $2; }
+        ;
+
+serial_attribute:
+          asrow_attribute
         | IDENT_sys equal TEXT_STRING_sys
           {
             if ($3.length > ENGINE_OPTION_MAX_LENGTH)