Question

1050. Actors and Directors Who Cooperated At Least Three Times

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Description

Table: ActorDirector

+-------------+---------+
| Column Name | Type  |
+-------------+---------+
| actor_id  | int   |
| director_id | int   |
| timestamp   | int   |
+-------------+---------+
timestamp is the primary key (column with unique values) for this table.

 

Write a solution to find all the pairs (actor_id, director_id) where the actor has cooperated with the director at least three times.

Return the result table in any order.

The result format is in the following example.

 

Example 1:

Input: 
ActorDirector table:
+-------------+-------------+-------------+
| 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       |
+-------------+-------------+-------------+
Output: 
+-------------+-------------+
| actor_id  | director_id |
+-------------+-------------+
| 1       | 1       |
+-------------+-------------+
Explanation: The only pair is (1, 1) where they cooperated exactly 3 times.

Solutions

Solution 1: Group By + Having

We can use the GROUP BY statement to group the data by the actor_id and director_id fields, and then use the HAVING statement to filter out the actor_id and director_id that appear at least three times.

# Write your MySQL query statement below
SELECT actor_id, director_id
FROM ActorDirector
GROUP BY 1, 2
HAVING COUNT(1) >= 3;