Mysql错误Every derived table must have its own alias解决方

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

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