Swap Salary

• LeetCode: Swap Salary

• Problem:

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.

• Examples:

| 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    |

• Analysis:

Use Update statement and CASE WHEN THEN to filter sex is m or f and set new values.

• SQL:

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