✔️ MySQL || Easiest Solution || Most efficient Solution ✔️
\nUPDATE salary\nSET\n    sex = CASE sex\n        WHEN \'m\' THEN \'f\'\n        ELSE \'m\'\n    END;\n
```\nUPDATE salary\nSET\n    sex = CASE sex\n        WHEN \'m\' THEN \'f\'\n        ELSE \'m\'\n    END;\n```
['MySQL', 'Oracle']