[LeetCode] 577. Employee Bonus_Easy tag: SQL

Select all employee's name and bonus whose bonus is < 1000.

Table:Employee

+-------+--------+-----------+--------+
| empId |  name  | supervisor| salary |
+-------+--------+-----------+--------+
|   1   | John   |  3        | 1000   |
|   2   | Dan    |  3        | 2000   |
|   3   | Brad   |  null     | 4000   |
|   4   | Thomas |  3        | 4000   |
+-------+--------+-----------+--------+
empId is the primary key column for this table.

Table: Bonus

+-------+-------+
| empId | bonus |
+-------+-------+
| 2     | 500   |
| 4     | 2000  |
+-------+-------+
empId is the primary key column for this table.

Example ouput:

+-------+-------+
| name  | bonus |
+-------+-------+
| John  | null  |
| Dan   | 500   |
| Brad  | null  |
+-------+-------+

Code

SELECT e.name, b.bonus FROM Employee as e LEFT JOIN Bonus as b ON e.empId = b.empId WHERE b.bonus IS NULL or b.bonus < 1000

# 不能直接用JOIN, 相当于inner join, 如果bonus没有的, 那么就没有了, 所以上面的例子只会输出Dan, 500 这一栏而已.