delete duplicate records in sql

SQL Duplicate record query 1, look for redundant records in the table, duplicate records are based on a single field (Peopleid) to judge SELECT * from people where Peopleid to (select Peopleid from People GROUP by Peopleid have count (Peopleid) > 1) Case Two

Title) Note: The maximum ID record is displayed here. Ii. Delete duplicate records 1. Delete All Repeated Records (use with caution) ? 1 Delete table Where repeated field In (Select repeated field From Table Group By repeated

Search for records with all repeated titles: SELECT * FROM t_info a WHERE ((SELECT COUNT(*) FROM t_info WHERE Title = a.Title) > 1) ORDER BY Title DESC 1. Search for duplicate records 1. Search for all Repeated Records Select * From table Where repeated field In (Select repeated field From Table Group By repeated fiel

There are many ways for SQLServer to search for and delete duplicate records in tables. Below I will list several commonly used SQL statements with good performance. If you need them, please refer to them. There are many ways for SQL Server to find and

Original post address: http://www.cnblogs.com/phpliu/archive/2010/06/21/1761726.html For example:ID name value1 A PP2 A PP3 B III4 B PP5 B PP6 c pp7 c pp8 C IIIID is the primary keyThis result is required.ID name value1 A PP3 B III4 B PP6 c pp8 C III Method 1Delete yourtableWhere [ID] Not in (Select max ([ID]) from yourtableGroup by (name + value )) Method 2DeleteFrom table a left join (Select (ID) from Table group by name, Value) B on A. ID = B. IDWhere B. ID is null

The SQL statement used to query multiple fields, query multiple tables, and delete duplicate records. SQL repeat record Query 1. Search for redundant duplicate records in the Table.

There are often repeated records in the database. sometimes I want to query duplicate records and display them, and sometimes I want to delete them. next I will introduce how to delete and query duplicate

SQL statement to query duplicate records and delete Repeated Records Search for records with all repeated titles: Select * From t_info A where (select count (*) from t_info where title = A. Title)> 1) Order by title DESC I. Searc

Quickly delete duplicate records in SQL Server 2006-07-17 21:53:15Category: SQL Server 　　 Developer's Nightmare-delete duplicate recordsPresumably, every developer has had

Nightmare for Developers--delete duplicate records Presumably 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

For example, there is a personnel table (table name: peosons)If you want to query records whose names, ID card numbers, and addresses are identical Select p1. * from persons p1, persons p2 where p1.id The above results can be achieved. Several SQL statements used to delete Repeated Records 1. Use the rowid Method 2. U

How to quickly delete duplicate records in SQL Server Developer nightmare-delete Repeated Records Presumably, every developer has had a similar experience. When querying or collecting statistics on the database, the query an

server| Repeat | Recurring nightmare for Developers--delete duplicate records Presumably 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 solut

SQL statements Delete duplicate records and retain only one record. Copy codeThe Code is as follows:Delete WeiBoTopics where Id in (select max (Id) from WeiBoTopics group by WeiBoId, Title having COUNT (*)> 1 ); SQL: delete

Developer nightmare-delete Repeated Records Presumably, every developer has had a similar experience. When querying or collecting statistics on the database, the query and statistics results may be inaccurate due to repeated records in the table. The solution to this problem is to delete these

Developer nightmare-delete Repeated RecordsPresumably, every developer has had a similar experience. When querying or collecting statistics on the database, the query and statistics results may be inaccurate due to repeated records in the table. The solution to this problem is to delete these duplicate

1. Find all duplicate records The code is as follows Copy Code SELECT * FROM table Where repeat field in (Select repeating field from table Group by repeating field having Count (*) >1) 2. Filter duplicate records (show only one) The code is as follows Copy Code

how much in thousands of records, there are some same records, how can you use SQL statements, delete duplicates1, look for redundant records in the table, duplicate records