第四章 求交集--intersect运算

select * from staff

intersect

select * from staff_copy;

mysql不支持,需要通过自己实现

SELECT id,name,level from (  

    SELECT id ,name ,level from staff  

    UNION ALL  

    SELECT id ,name ,level  from staff_copy  

)a 

GROUP BY id,name,level

 HAVING count(*)>1  

 如果字段名称不一样的话需要

 SELECT c_id,name,level from (  

    SELECT id  as c_id,name ,level from staff  

    UNION ALL  

    SELECT id1 as c_id ,name ,level  from staff_copy  

)a   

GROUP BY c_id,name,level

 HAVING count(*)>1