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QuXiangjie / Study-Review

自己欠缺的还太多了，希望通过总结每天的学习内容，整理每天的思绪来丰富自己的知识库。我想成为一名优秀的金融数据分析师，并行发展技术与商业业务。博客内容为：数理统计、财务业务、Python(数据分析及可视化)、Excel（数据分析）、SQL、英文
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182. Duplicate Emails #10

Open QuXiangjie opened 5 months ago

QuXiangjie commented 5 months ago

Question

select distinct P1.email as Email
from Person as P1, Person as P2
where P1.email=P2.email
group by P1.id
having count(P2.email)>=2

High efficient way

SELECT DISTINCT P1.Email FROM Person P1,Person P2 

WHERE P1.id <> P2.id AND P1.Email=P2.Email
QuXiangjie commented 4 months ago 
select distinct P1.email as Email
from Person as P1
group by P1.email
having count(P1.id)>1