Easy之1050.合作过至少三次的演员和导演

Love The Way You Lie 2022-10-07 10:58 70阅读 0赞

### ActorDirector 表： ###

<table> 
 <thead> 
  <tr> 
   <th>Column Name</th> 
   <th>Type</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>actor_id</td> 
   <td>int</td> 
  </tr> 
  <tr> 
   <td>director_id</td> 
   <td>int</td> 
  </tr> 
  <tr> 
   <td>timestamp</td> 
   <td>int</td> 
  </tr> 
 </tbody> 
</table>

timestamp 是这张表的主键.

### 问题 ###

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： ####

<table> 
 <thead> 
  <tr> 
   <th>actor_id</th> 
   <th>director_id</th> 
   <th>timestamp</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>1</td> 
   <td>1</td> 
   <td>0</td> 
  </tr> 
  <tr> 
   <td>1</td> 
   <td>1</td> 
   <td>1</td> 
  </tr> 
  <tr> 
   <td>1</td> 
   <td>1</td> 
   <td>2</td> 
  </tr> 
  <tr> 
   <td>1</td> 
   <td>2</td> 
   <td>3</td> 
  </tr> 
  <tr> 
   <td>1</td> 
   <td>2</td> 
   <td>4</td> 
  </tr> 
  <tr> 
   <td>2</td> 
   <td>1</td> 
   <td>5</td> 
  </tr> 
  <tr> 
   <td>2</td> 
   <td>1</td> 
   <td>6</td> 
  </tr> 
 </tbody> 
</table>

#### Result 表： ####

<table> 
 <thead> 
  <tr> 
   <th>actor_id</th> 
   <th>director_id</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>1</td> 
   <td>1</td> 
  </tr> 
 </tbody> 
</table>

唯一的 id 对是 (1, 1)，他们恰好合作了 3 次。  
来源：力扣（LeetCode）  
链接：https://leetcode-cn.com/problems/actors-and-directors-who-cooperated-at-least-three-times  
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### 解答 ###

select actor_id,director_id
    from ActorDirector
    group by actor_id,director_id
    having count(actor_id)>2

##### 长知识 #####

学到了group by 后面还可以跟两个字段