要求:写一条SQL查询语句获取合作过至少三次的演员和导演的 id 对 (actor_id, director_id)。
ActorDirector 表的结构:
+-------------+---------+
| Column Name | Type |
+-------------+---------+
| actor_id | int |
| director_id | int |
| timestamp | int |
+-------------+---------+
timestamp 是这张表的主键.。
ActorDirector 表:
ActorDirector 表:
+-------------+-------------+-------------+
| actor_id | director_id | timestamp |
+-------------+-------------+-------------+
| 1 | 1 | 0 |
| 1 | 1 | 1 |
| 1 | 1 | 2 |
| 1 | 2 | 3 |
| 1 | 2 | 4 |
| 2 | 1 | 5 |
| 2 | 1 | 6 |
+-------------+-------------+-------------+
Result Table:
+-------------+-------------+
| actor_id | director_id |
+-------------+-------------+
| 1 | 1 |
+-------------+-------------+
分析:
1.通过演员id和导演id分组,取得合作次数大于等于三的演员和导演id即最终结果
SQL语句:
select actor_id,director_id
from ActorDirector
group by actor_id,director_id
having count(*)>=3;
本文介绍了一条SQL查询语句,用于从ActorDirector表中筛选出合作超过三次的演员和导演组合。通过分组和计数的方法实现精确匹配。
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