表全部資料

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1 查詢people_no重複的記錄

select * from people
where people_no in (select   people_no from   people group by   people_no having count(people_no) > 1);

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2 查詢people_no重複的記錄 ，排除最小id，如果刪除改為delete from

select * from people
where people_no in (select   people_no from people group by   people_no   having count(people_no) > 1) and  
id not in (select min(id) from   people group by people_no having count(people_no)>1);

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3 查詢people_no people_name重複的記錄

select * from people a
where (a.people_no,a.people_name) in (select people_no,people_name from people GROUP BY people_no,people_name HAVING count(*)>1);

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4 查詢people_no people_name重複的記錄，排除最小id

select * from people a
where (a.people_no,a.people_name) in (select people_no,people_name from people GROUP BY people_no,people_name HAVING count(*)>1) and
a.id not in    (select min(id) from people GROUP BY people_no,people_name HAVING count(*)>1);