弄了好久，结果发现-------- 因为mysql没有full join这个东西
你只能写成
sleect * from A left join B on A.id=B.id
union
select * from A.right join B on A.id=B.id
select person.FirstName,person.LastName,orders.OrderNo
from person
LEFT JOIN orders
ON person.id_p=orders.Id_p
UNION
select person.FirstName,person.LastName,orders.OrderNo
from person
RIGHT JOIN orders
ON person.id_p=orders.Id_p;
shit-------------mysql没有full join 语句
原文：http://www.cnblogs.com/zzzzw/p/4964454.html
