case when对数据进行选择

leetcode 627. Swap Salary

将表中的sex字段的m和f互换

# Write your MySQL query statement below
update salary set
sex = case sex 
when 'm' then 'f' 
else 'm'
end

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 statement and no intermediate temp table.

Note that you must write a single update statement, DO NOT write any select statement for this problem.
Example:

After running your update statement, the above salary table should have the following rows: