2356. Number of Unique Subjects Taught by Each Teacher
Easy
78
6
SQL Schema

Table: Teacher

+-------------+------+
| Column Name | Type |
+-------------+------+
| teacher_id  | int  |
| subject_id  | int  |
| dept_id     | int  |
+-------------+------+
(subject_id, dept_id) is the primary key for this table.
Each row in this table indicates that the teacher with teacher_id teaches the subject subject_id in the department dept_id.

 

Write an SQL query to report the number of unique subjects each teacher teaches in the university.

Return the result table in any order.

The query result format is shown in the following example.

 

Example 1:

Input: 
Teacher table:
+------------+------------+---------+
| teacher_id | subject_id | dept_id |
+------------+------------+---------+
| 1          | 2          | 3       |
| 1          | 2          | 4       |
| 1          | 3          | 3       |
| 2          | 1          | 1       |
| 2          | 2          | 1       |
| 2          | 3          | 1       |
| 2          | 4          | 1       |
+------------+------------+---------+
Output:  
+------------+-----+
| teacher_id | cnt |
+------------+-----+
| 1          | 2   |
| 2          | 4   |
+------------+-----+
Explanation: 
Teacher 1:
  - They teach subject 2 in departments 3 and 4.
  - They teach subject 3 in department 3.
Teacher 2:
  - They teach subject 1 in department 1.
  - They teach subject 2 in department 1.
  - They teach subject 3 in department 1.
  - They teach subject 4 in department 1.
Accepted
12.7K
Submissions
14.5K
Acceptance Rate
88.0%

Seen this question in a real interview before?
1/4
Yes
No

Discussion (0)

Related Topics
Copyright ©️ 2023 LeetCode All rights reserved