627-swap_salary.sql

-- 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    |


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