627, 1965 (leetcode)

627.Swap Salary

https://leetcode.com/problems/swap-salary/?envType=study-plan&id=sql-i

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

1965. Employees With Missing Information

SELECT A.employee_id FROM Employees A LEFT JOIN Salaries B ON A.employee_id = B.employee_id WHERE salary is null
union
SELECT B.employee_id FROM Employees A RIGHT JOIN Salaries B ON A.employee_id = B.employee_id WHERE name is null
ORDER BY employee_id