delete duplicate records in sql

: I created a table in ms SQL, but some records are repeated for various reasons.: The records are exactly the same.: Now I want to delete all the duplicates and only keep the first record.: I see oracle introduction in the database,Select distinct * into # table_name from table_nameDelete from table_nameSelect * into

Find records for all duplicate headings: SELECT * from T_info a WHERE (SELECT COUNT (*) from t_info where title = A.title) > 1) Order by Title DESC First, find duplicate records 1. Find all duplicate records SELECT * FROM tabl

Wen/Xiachong Nightmare for Developers--delete duplicate recordsPresumably every developer has had a similar experience, and when querying or counting the database, the query and statistic results are inaccurate due to duplicate records in the table. The solution to this problem is to

Delete duplicate records and save TABLE_NAME Records in #table_name SELECT DISTINCT * INTO #table_name table_name Delete from table_name SELECT * INTO table_name from #table_name drop table #table_name Related to this is the "SELECT INTO" option, which can be used in datab

Test data preparationGive Test_user access to the Scott User EMP table Grant Select on to Test_user;Use Test_user to create an EMP table based on the Scott User's EMP table Create Table as Select * from Scott.emp;Insert the same data again Insert into Select * from EMP;Querying Current data Select * from Order by ASC;You can see that each record appears twice.Delete duplicate records1, delete redund

After learning about SQL for a while, I found a lot of duplicate records in the table I built to test (not indexed). Later, we summarize some ways to delete duplicate records, in Oracle, you can

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

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]) Valu

The code is as follows Copy Code Select A.*From temp a INNER join (select Name,sex to Temp GROUP by Name,sex has count (*) >1) bOn a.name = b.name and a.sex = B.sex To see a delete duplicate record instance User table structureCREATE TABLE User (varchar (uname) notnull;varchar (upass);); The code is as follows Copy Code Create a temporary table and cop

1. Using the rowID method 2. Using the group by method 3. Using the Distinct method 1. Using rowID method According to the Oracle band ROWID attribute, to determine whether there are duplicates, the statement is as follows:Check the data: SELECT * FROM table1 a where rowID!= (select Max (ROWID) From table1 b where a.name1=b.name1 and a.name2=b.name2 ...) Delete data: Delete from

Background: Today, when I used a crawler to crawl data, I was accidentally suspended when I first crawled data. Later, I started again, but forgot to clear some junk data, as a result, many repeated records are generated in the wordlocation table. The wordlocation table defines the following wordlocation (urlid, wordid, location), where (urlid, wordid) should be unique. Requirements: Remove redundant duplicate