how to eliminate duplicate records in sql

During this time, the project needs to import the original data to the new database, and the duplicate data needs to be deleted. I use the cursor method to solve this problem. The SQL statement is as follows to avoid forgetting. Code Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/--> -- Delete duplicate data

SQL statements for querying and deleting duplicate records ASayThere is a field "name" in Table A,and the "name" value may be the same between different records,Now you need to query the records in the table, the "name" value duplicates the item; Select Name,count (*) fr

IF object_id('Carddetail') is not NULL DROP TABLECarddetailCREATE TABLECarddetail (IDINT IDENTITY(1,1)PRIMARY KEY, CardnoVARCHAR(8), NAMEVARCHAR( -), IdcardVARCHAR( -), CardstateCHAR(1)--card Status 1 Normal 2 logoff ) INSERTCarddetail (cardno,name,idcard,cardstate)VALUES ('001','Zhang San','31010',1), ('005','Zhang San','31010',1), ('002','John Doe','31011',1), ('003','Harry','31012',1), ('006','Zhang San','31010',0), ('004','Harry','31012',1), ('007','Ouyang','31013',1), ('008','Ouyang','3

Tags: SQL multi-condition sieve weightUsually we check the weight, and filter the duplicates according to a certain condition.SELECT * FROM dbo. T_ecert Awhere (A.ecertid) in (select Ecertid from T_ecert GROUP by Ecertid+idcard have count (*) > 1)But what if you need to have multiple conditions?Oracle can do thisSELECT * FROM dbo. T_ecert Awhere (A.ecertid,a.idcard) in (select A.ecertid,a.idcard from T_ecert GROUP by Ecertid,idcard have count (*) > 1)

: I built a table in MS SQL, but for a variety of reasons some records are duplicated : The record is exactly the same. : Now I want to delete the duplicates, just keep the first one in the duplicate record. : I seem to have seen a presentation of Oracle in the database, SELECT DISTINCT * INTO #table_name table_name Delete from table_name SELECT * INTO table_name

Repeat: I built a table in MS SQL, but for a variety of reasons some records are duplicated : The record is exactly the same. : Now I want to delete the duplicates, just keep the first one in the duplicate record. : I seem to have seen a presentation of Oracle in the database, SELECT DISTINCT * INTO #table_name table_name Delete from table_name SELECT * INTO

Let's now look at how to delete these records in SQL SERVER 2008, first of all, to simulate making some simple duplicate records: Copy Code code as follows: Create Table dbo. Employee ( [Id] int Primary KEY, [Name] varchar (50), [Age] int, [Sex] Bit default 1 ) Insert into Employee ([Id], [Name], [ag

Tags: class delete highlight top update duplicate record color Xiaomi dateInsert duplicates when inserting data accidentally todayThere are no primary key foreign keys in this table, you may insert or delete them arbitrarily.There's a lot of complicated statements on the web that don't solve the problem.Finally, use delete top (1) to solve the problemDelete Top (1from where='xiaomin'can also be usedUpdate Top (1) from the person where name = ' xxxx '

Let's take a look at how you can use it to delete duplicate records in a table: Copy Code code as follows: If Exists (Select * FROM Tempdb.Information_Schema.Tables Where table_name like ' #Temp% ') Drop Table #temp Create Table #temp ([Id] int, [Name] varchar, [age] int, [SEX] bit default 1) Go Insert into #temp ([Id], [Name], [age], [Sex]) Values (1, ' James ', 25,default) Insert into #t

One, query a field repeat Copy Code code as follows: SELECT * From User u where U.user_name in (select U.user_name From User u GROUP BY U.user_name has count (*) > 1) Two, delete the duplicate of a few fields in the table Example: There are six records in the table. Where John and Harry records are duplicated.TableA Copy Co