627. Swap Salary

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

# Write your MySQL query statement below
UPDATE salary
    SET sex  = (CASE WHEN sex = 'm' 
        THEN  'f'
        ELSE 'm'
        END)

转载于:https://www.cnblogs.com/bernieloveslife/p/9800593.html