_627.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 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:
--
--| 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    |

--solution 1:
update salary
set sex = CHAR(ASCII('f') ^ ASCII('m') ^ ASCII(sex));

--solution 2:
update salary
set sex = case sex
    when 'm' then 'f'
    else 'm'
    end;