delete duplicate records in sql

This article introduces how to use havinggroupby and various selectin joint queries to filter the SQL language names of Repeated Records in different ways. This article introduces how to use having group by and various select in joint queries to filter the SQL language names of Repeated Records in different ways. 1.

Delete a duplicate data SQL statementMethod One Suppose there is a duplicate field of name,address that requires a unique result set for both fieldsSelect Identity (int,1,1) as Autoid, * into #tmp from TableNameSelect min (autoid) as autoid into #tmp2 from #tmp Group by name,autoidSELECT * from #tmp where autoid in (s

My most common method is The code is as follows Copy Code Delete ID duplicate data, suitable for ID is manual primary keyDelete Person as a from as a,(Select *,min (ID) from person GROUP by ID having count (1) > 1) as Bwhere a.id = b.ID Look for duplicates and get rid of the smallest one. The code is as follows Copy Code

SQL statement for querying and deleting duplicate records1. Search for redundant duplicate records in the Table. duplicate records are determined based on a single field (peopleid ).Select * from peopleWhere peopleid in (select pe

Webjxcom prompt: for example, if you want to query records with the same name, ID card number, and address in the current table (table name: peosons), select P1. * from persons P1, persons P2 where p1.idp2. ID and p1.cardid = p2.cardid and p1.pname = p2.pname and p1.address = p2.address. quantity For example, there is a personnel table (table name: peosons)If you want to query records whose names, ID

Method One Copy Code code as follows: Declare @max integer, @id integer Declare cur_rows cursor Local for select main field, COUNT (*) from table name Group by main field having count (*) > 1 Open Cur_rows Fetch cur_rows into @id, @max While @ @fetch_status =0 Begin Select @max = @max-1 SET ROWCOUNT @max Delete from table name where main field = @id Fetch cur_rows into @id, @max End Close Cur_rows SET ROWCOUNT

DatabaseThe use of the process due to procedural problems sometimes encounter duplicate data, duplication of data caused the database part of the settings can not be set correctly ...Method Onedeclare @max integer,@id integerdeclare cur_rows cursor local for select 主字段,count(*) from 表名 group by 主字段 having count(*) > 1open cur_rowsfetch cur_rows into @id,@maxwhile @@fetch_status=0beginselect @max = @max -1set rowcount @maxdelete from 表名 where 主字段 = @id

This tutorial provides two SQL statement codes for deleting duplicate records. One is to use wherein to query duplicate records and then delete them. The other is to use innerjoin to delete