mysql查找重复数据(Mysql to find the duplicate data).doc

mysql查找重复数据(Mysql to find the duplicate data).doc

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mysql查找重复数据(Mysql to find the duplicate data)

mysql查找重复数据(Mysql to find the duplicate data) Method for querying and deleting duplicate records (a) 1, find redundant redundant records in the table, and repeat records are judged by a single field (peopleId) Select * from people Where peopleId in (select, peopleId, from, people, group, by, peopleId, having, count (peopleId) ,) 2, delete redundant duplicate records in the table, repeat records are based on a single field (peopleId) to determine, leaving only the smallest record of ROWID Delete from people Where peopleId in (select, peopleId, from, people, group, by, peopleId, having, count (peopleId) ,) And, ROWID, not, in (select, min (ROWID), from, people, group, by, peopleId, having, count (peopleId), 1) 3, find redundant duplicate records in the table (multiple fields) Select * from vitae a Where (a.peopleId, a.seq), in (select, peopleId, SEQ, from, vitae, group, by, peopleId, SEQ, having, count (*) , 1) 4, delete redundant duplicate records (multiple fields) in the table, leaving only the smallest record of ROWID 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 、 find redundant duplicate records (multiple fields) in the table, and do not contain the minimum record of ROWID 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) (two) For example There is a field name in the A table, Also, the name value between the different records might be the same, Now you need to check out the records between the tables, and the name value has duplicate entries; Select, Name, Count (*), From, A, Group, By, Name, Having, Count (*) 1 If you also check the same gender, the following are the following: Selec

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