Made the combination of INTO and FROM DUAL work, e.g.
SELECT 1 INTO @x FROM DUAL.
As a consequence, DUAL is made a reserved word. It would work to not have
it reserved, but it was deemed to be confusing as a user defined table by
the same name then must be qualified with a db (schema).


sql/sql_yacc.yy:
  Made the combination of INTO and FROM DUAL work, e.g.
  SELECT 1 INTO @x FROM DUAL.
  As a consequence, DUAL is made a reserved word. It would work to not have
  it reserved, but it was deemed to be confusing as a user defined table by
  the same name then must be qualified with a db (schema).