Mysql错误Every derived table must have its own alias解决办法

[SQL] SELECT * from 
(
select e.account from employee e
UNION
SELECT u.account from `user` u
UNION
SELECT a.account from agent a
)
[Err] 1248 - Every derived table must have its own alias

SELECT * from 
(
select e.account from employee e
UNION
SELECT u.account from `user` u
UNION
SELECT a.account from agent a
)as total