在几千条记录里,存在着些相同的记录,如何能用SQL语句,删除掉重复的呢?
  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)  

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