SQL重复记录查询和删除方法

发表于:2016-11-25 09:50

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 作者:爱在红旗渠    来源:51Testing软件测试网采编

  MYSQL 查询和删除重复记录的方法很多,下面就为您介绍几种最常用的 MYSQL 查询和删除重复记录的方法,希望对您查询和删除重复数据方面能有所帮助。
  SQL重复记录查询的几种方法:
  1. 查找表中多余的重复记录,重复记录是根据单个字段(peopleId)来判断
  select * from people
  where peopleId
  in (select peopleId from people
  group by peopleId
  having count(peopleId) > 1)
  2. 删除表中多余的重复记录,重复记录是根据单个字段(peopleId)来判断,只留有 rowid 最小的记录
  delete from people
  where peopleId
  in (select peopleId from people
  group by peopleId
  having count(peopleId) > 1)
  and rowid not in (
  select min(rowid) from people
  group by peopleId
  having count(peopleId)>1)
  3. 查找表中多余的重复记录(多个字段)
  select * from vitae a
  where (a.peopleId,a.seq)
  in (select peopleId,seq from vitae
  group by peopleId,seq
  having count(*) > 1)
  4. 删除表中多余的重复记录(多个字段),只留有 rowid 最小的记录
  delete from vitae a
  where (a.peopleId,a.seq)
  in (select peopleId,seq from vitae
  group by peopleId,seq
  having count(*) > 1)
  and rowid not in (
  select min(rowid) from vitae
  group by peopleId,seq having count(*)>1)
  5. 查找表中多余的重复记录(多个字段),不包含 rowid 最小的记录
  select * from vitae a
  where (a.peopleId,a.seq)
  in (select peopleId,seq from vitae
  group by peopleId,seq
  having count(*) > 1)
  and rowid not in (
  select min(rowid) from vitae
  group by peopleId,seq
  having count(*)>1)
  以上 SQL 记录重复数据查询和删除方法,希望能够帮助你。
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