Given a table salary, such as the one below, that has m=male and f=female values. Swap all f and m values (i.e., change all f values to m and vice versa) with a single update query and no intermediate temp table.

For example:

id	name	sex	salary
1	A	m	2500
2	B	f	1500
3	C	m	5500
4	D	f	500
After running your query, the above salary table should have the following rows:
id	name	sex	salary
----	------	-----	--------
1	A	f	2500
2	B	m	1500
3	C	f	5500
4	D	m	500
也是简单的sql题目
但是。。我已经还给老师了，看了看答案。完成了AC。

Write your MySQL query statement below

Update salary SET sex = CASE sex WHEN 'f' THEN 'm' ELSE 'f' END;