Swap Salary
Desicription
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:
代码语言:javascript复制| 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:
代码语言:javascript复制| id | name | sex | salary |
|----|------|-----|--------|
| 1 | A | f | 2500 |
| 2 | B | m | 1500 |
| 3 | C | f | 5500 |
| 4 | D | m | 500 |
Solution
代码语言:javascript复制update salary set sex = char(ascii('m') ascii('f') - ascii(sex));