1. 查找重复记录
如果只是不想在查询结果中存在重复记录, 可以加Distinct
select distinct * from TestTable如果是想查询重复的记录及其数量
select UserID,UserName,count(*) as '记录数'
from TestTable
Group by UserID,UserName
having count(*)>1
ID不重复, 但是字段重复的记录只显示一条如果只是不想在查询结果中存在重复记录, 可以加Distinct
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2. 删除重复记录
一种思路是利用临时表, 把查询到的无重复记录填充到临时表, 再把临时表的记录填充回原始表
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(group by 的字段, 有点麻烦).
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