leetcode.672 Swap Salary

Example:

id	name	sex	salary
1	A	m	2500
2	B	f	1500
3	C	m	5500
4	D	f	500

After running your update statement, 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

使用 sql swap 表中的 sex 字段，不能用select，是能使用 update

update salary set sex = IF(sex = 'm', 'f', 'm');

update salary set sex = CHAR(ASCII('f') ^ ASCII('m') ^ ASCII(sex));

update salary set sex = (case when sex='m' then 'f' when sex='f' then 'm' end)