delete duplicate rows in sql

Find duplicate data T-SQL in the database ========== first article ============ there are duplicate records under a field in a table, there are many ways, however, there is a method that is relatively efficient. The following statement: Select data_guid from adam_entity_datas A where. rowid> (select Min (B. rowid) from adam_entity_datas B where B. data_guid =. da

; CREATE TABLE TMP2 Select tablename.* from tablename,tmp where tablename.autoid = tmp.autoid; drop TABLE TableName; Rename table Tmp2 to TableName; SQL Server Select Identity (int,1,1) as Autoid, * into #Tmp from TableName; Select min (autoid) as autoid into #Tmp2 from #Tmp Group by name,address; drop TABLE TableName; SELECT * INTO TableName from #Tmp where autoid in (select Autoid from #Tmp2); drop table #Tmp; drop table #Tmp2; Oracle

Query and delete duplicate records SQL statement 1, find redundant records in the table, duplicate records are based on a single field (ID) to determine select * from table where Id in (select Id from table group Byid having count (ID) > 1) 2, delete redundant records in the

There are many ways to delete duplicate records. Here I summarize a variety of SQL statements for deleting restart records, such as deleting duplicate id data and searching for duplicate records, remove the smallest record, delete

Tags: here SQ delete duplicate data img class from ROM route sameDirectly on SQL: Method one:Delete fromRoutewhereIdinch(Selectb.ID from(Select * fromRoute AwhereId(Select min(ID) fromRoutewherePayment_type=0 andPoint_start=A.point_start andPoint_end=a.point_end)) b);Question: a route table. Now you need to delete,

figure 1, the records of product Chang and Tofu are repeated in the product information table. To delete these duplicate records, only one of them is retained. The procedure is as follows: The first axe -- create a temporary table with the same structure Create table Products_temp (ProductID int,ProductName nvarchar (40 ),Unit char (2 ),UnitPrice money) Second Board ax-add an index to the t

Deleting duplicate rows on SQL Server is one of the most common operations. The following describes six methods that can be used to delete duplicate rows on SQL Server for your referenc

SQL server calculates the value of a field in the database, removes duplicate data, and SQL server Sometimes, some duplicate data exists in the database, but we want to calculate the value of a field, and we need to remove the duplicate data ,: In the preceding figure, we c

table tmp_wrap;Query OK, 0 rows affected (0.05 sec) 2. There is also a very streamlined approach. Find the duplicate and remove the smallest one. The Code is as follows: Delete users_groups as a from users_groups as,(Select *, min (id) from users_groups group by uid having count (1)> 1) As BWhere a. uid = B. uid and a. id> B. id;

table group by name)Delete from table where field in (Select field from Table group By field has count (*) > 1)The above method is also useful when deleting a small order of data, and when the data is processed by hundreds of thousands of or more, the general machine estimates that it will be paid as soon as it runs. In fact, a little bit of common sense is to know that such a statement will have a large amount of computation, and its operation is at

Each time you import an Excel table to the database, several more rows are displayed as 'null' rows. The following prompt is displayed when you delete the table. "The key column information is insufficient or incorrect. Update affects multiple rows! " Solution: You can see from your description that you have imported

Label: Suppose you have a table of people (table name: person), if you want to name, ID number, address the three fields exactly the same records to find out, using 1: SELECT p1.* 2: From persons p1,persons p2 3: WHERE p1.id 4: And p1.cardid = p2.cardid 5: And p1.pname = p2.pname 6: And p1.address = p2.address This functionality can be implemented. SQL