mysql/mybatis之合并两个表的查询结果

下面这段sql是把两个表中各自符合条件的count值相加,返回结果是两个之和

SELECT sum(result) FROM
        (
          SELECT COUNT(*) result FROM TEST_A WHERE name= #{param} OR desc= #{param}  UNION ALL
          SELECT COUNT(*) result FROM TEST_B WHERE name= #{param}
        ) a