문제
https://leetcode.com/problems/count-salary-categories/?envType=study-plan-v2&envId=top-sql-50
설명
처음에는 UNION ALL을 이용해서 income 컬럼을 기준으로 각 카테고리별로 count 는 구했지만 카테고리 컬럼을 추가하지 못했다.
컬럼을 추가하려면, SELECT "value" AS 컬럼명 을 하면 된다!
=> 행을 추가할 땐, UNION ALL, 열을 추가할 땐 SELECT 을 이용하자.
구현
# Write your MySQL query statement below
( SELECT 'Low Salary' AS category, count(*) AS accounts_count
FROM Accounts a
WHERE a.income < 20000 )
UNION ALL
( SELECT 'Average Salary' AS category, count(*) AS accounts_count
FROM Accounts a
WHERE a.income >= 20000 AND a.income <=50000 )
UNION ALL
( SELECT 'High Salary' AS category, count(*) AS accounts_count
FROM Accounts a
WHERE a.income > 50000 )'Coding > SQL' 카테고리의 다른 글
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