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182. Duplicate Emails 본문
https://leetcode.com/problems/duplicate-emails/
Duplicate Emails - LeetCode
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leetcode.com
Solution
SELECT Email
FROM Person
GROUP BY Email
HAVING COUNT(Email) > 1- Email이 같은 항목의 개수를 보고 중복되는 데이터를 반환한다.
- GROUP BY ... HAVING 을 이용하여 중복되는 데이터를 묶는다.
- COUNT 를 이용하여 중복되는 데이터를 센다.
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