题目
ActorDirector 表：
+-------------+---------+ | Column Name | Type | +-------------+---------+ | actor_id | int | | director_id | int | | timestamp | int | +-------------+---------+ timestamp 是这张表的主键.
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)
示例：
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 表： +-------------+-------------+ | actor_id | director_id | +-------------+-------------+ | 1 | 1 | +-------------+-------------+ 唯一的 id 对是 (1, 1)，他们恰好合作了 3 次。
解题
select actor_id,director_id from ActorDirector group by actor_id,director_id having count(*)>=3;
