Function cmp_unit_op

sql/sql_lex.h:115–120

};

inline int cmp_unit_op(enum sub_select_type op1, enum sub_select_type op2)
{
  DBUG_ASSERT(op1 >= UNION_TYPE && op1 <= EXCEPT_TYPE);
  DBUG_ASSERT(op2 >= UNION_TYPE && op2 <= EXCEPT_TYPE);
  return (op1 == INTERSECT_TYPE ? 1 : 0) - (op2 == INTERSECT_TYPE ? 1 : 0);
}

enum unit_common_op {OP_MIX, OP_UNION, OP_INTERSECT, OP_EXCEPT};