#105. [LeetCode / MySQL] 1789. Primary Department for Each Employee

문제

 

입력 코드

1. 

SELECT employee_id, department_id
FROM Employee
GROUP BY employee_id
HAVING COUNT(employee_id) = 1
UNION
SELECT employee_id, department_id
FROM Employee
WHERE primary_flag = 'Y'

 

2.

SELECT DISTINCT employee_id, department_id
FROM Employee
WHERE employee_id IN (
    SELECT employee_id
    FROM Employee
    GROUP BY employee_id
    HAVING COUNT(*) = 1
  )
  OR primary_flag = 'Y'
ORDER BY employee_id;

 

 

코드 설명

#SELECT #GROUP BY #HAVING #COUNT #UNION #DISTINCT #ORDER BY

 

 

문제 출처

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