[#MDEV-10036] sql_yacc.yy: Split select_part2 to disallow syntactically bad constructs with INTO, PROCEDURE, UNION

sql_yacc.yy has the following code:

select_part2:

          select_options_and_item_list

          opt_order_clause

          opt_limit_clause

          opt_select_lock_type

        | select_options_and_item_list into opt_select_lock_type

        | select_options_and_item_list

          opt_into

          table_expression

          opt_order_clause

          opt_limit_clause

          opt_procedure_clause

          opt_into

          opt_select_lock_type

            if ($2 && $7)

              /* double "INTO" clause */

              my_error(ER_WRONG_USAGE, MYF(0), "INTO", "INTO");

              MYSQL_YYABORT;

            if ($6 && ($2 || $7))

              /* "INTO" with "PROCEDURE ANALYSE" */

              my_error(ER_WRONG_USAGE, MYF(0), "PROCEDURE", "INTO");

              MYSQL_YYABORT;

This task will refactor select_part2 to disallow wrong constructs so instead of

Incorrect usage of INTO and INTO

Incorrect usage of INTO and PROCEDURE

Incorrect usage of INTO and UNION

Incorrect usage of UNON and PROCEDURE

the parser will generate "syntax error", like this:

SELECT * FROM t1 LIMIT 1  UNION ALL SELECT 1;

ERROR 1064 (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 'UNION ALL SELECT 1' at line 1

Note, this change will not affect subselects, they will still return "Incorrect usage":

SELECT (SELECT * FROM t1 LIMIT 1  UNION ALL SELECT 1);

ERROR 1221 (HY000): Incorrect usage of UNION and LIMIT

Subselect will be fixed in a separate patch. We'll do one small step at a time!

[MDEV-10036] sql_yacc.yy: Split select_part2 to disallow syntactically bad constructs with INTO, PROCEDURE, UNION Created: 2016-05-06 Updated: 2016-05-10 Resolved: 2016-05-10
Status:	Closed
Project:	MariaDB Server
Component/s:	Parser
Fix Version/s:	10.2.1

[MDEV-10036] sql_yacc.yy: Split select_part2 to disallow syntactically bad constructs with INTO, PROCEDURE, UNION Created: 2016-05-06 Updated: 2016-05-10 Resolved: 2016-05-10