Disallow syntactically INSERT .. SELECT .. {ORDER BY ..| LIMIT ..} .. UNION ..

INSERT INTO t3 SELECT 1 ORDER BY 1 UNION SELECT 2;

INSERT INTO t3 SELECT 1 LIMIT 1 UNION SELECT 2;

CREATE TABLE t1 AS SELECT 1 ORDER BY 1 UNION SELECT 2;

CREATE TABLE t1 AS SELECT 1 LIMIT 1 UNION SELECT 2;

  if (lex->current_select->order_list.first && !lex->current_select->braces)

  {

    my_error(ER_WRONG_USAGE, MYF(0), "UNION", "ORDER BY");

    return TRUE;

  }

  if (lex->current_select->explicit_limit && !lex->current_select->braces)

  {

    my_error(ER_WRONG_USAGE, MYF(0), "UNION", "LIMIT");

    return TRUE;

  }