大数据面试SQL043 计算出完成订单数的众数

一、题目

现有用户订单表，请计算用户完成订单数的众数

+----------+-----------+----------------------+
| user_id  | order_id  |      order_time      |
+----------+-----------+----------------------+
| 1        | 1001      | 2024-02-25 08:00:00  |
| 1        | 1002      | 2024-02-25 09:30:00  |
| 2        | 1003      | 2024-02-25 10:45:00  |
| 2        | 1004      | 2024-02-25 12:15:00  |
| 2        | 1005      | 2024-02-25 13:45:00  |
| 3        | 1006      | 2024-02-25 15:00:00  |
| 4        | 1007      | 2024-02-25 16:30:00  |
| 4        | 1008      | 2024-02-25 18:00:00  |
| 1        | 1009      | 2024-02-26 07:45:00  |
| 1        | 1010      | 2024-02-26 09:15:00  |
| 1        | 1011      | 2024-02-26 10:30:0