duplicate annihilator

Duplicate data can be in two cases, the first: only some of the fields in the table, and the second is exactly the same as two rows of records. one, for partial field duplicate data deletion 1. Query for duplicate dataSelect field 1, Field 2, COUNT (*) from table name Group By field 1, Field 2 having count (*) > 1Example: Select owner from Dba_tables Group By Own

SQL statement for querying and deleting duplicate records 1, look for redundant records in the table, duplicate records are based on a single field (Peopleid) to determineSELECT * from Peoplewhere Peopleid in (select Peopleid from People GROUP by Peopleid have count (Peopleid) > 1) 2, delete redundant records in the table, duplicate records are based on a single

Label:MySQL handles duplicate dataThere may be duplicate records in some MySQL data tables, and in some cases we allow duplicate data, but sometimes we also need to delete the duplicated data. In this section we will show you how to prevent data tables from repeating data and how to delete duplicate data from a data ta

Mysql "on duplicate key update" syntaxIf the on duplicate key update is specified at the end of the INSERT statement and the DUPLICATE value appears in a UNIQUE index or primary key after the row is inserted, UPDATE is executed ON the row with the DUPLICATE value; if the unique value column is not

We often encounter the need to delete repeated records in a data table. Below I will summarize several methods that can delete Repeated Records and help to improve efficiency. For more information, see. We often encounter the need to delete repeated records in a data table. Below I will summarize several methods that can delete Repeated Records and help to improve efficiency. For more information, see. Create a table to store the id of the record to be deleted: The Code is as follow

There may be duplicate records in some MySQL data tables, and in some cases we allow duplicate data, but sometimes we also need to delete the duplicated data.Prevent duplicate data from appearing in a tableYou can set the specified field in the MySQL data table PRIMARY key (primary key) or unique (unique) index to guarantee the uniqueness of the data.Let's try an

The 11g Rman duplicate personal feel is a lot more advanced than 10g, 10g needs to replicate on the basis of Rman backup, using Rman duplicate to create a database with identical data but dbid different. The 11g Rman duplicate can be implemented in two ways using active database duplicate and backup-based duplicate.The

for testing. Can I have another virtual operating system ?) If there are multiple machines, this operation is very easy and requires few steps: 1. Create a secondary instance. 2. Connect Rman and run the duplicate command. It is really too simple, right? Well, I'll give you some trouble. Note that step 1 has several prerequisites for its execution. In other words, the great oracle adults once again delegated its noble power and gave you the following

On DUPLICATE key Update Bulk update MySQL has a batch update method, MSSQL No this command usage, MySQL This method can be used to batch update, more powerful is: if the parameter already exists update, if the database does not have this parameter inserted new. Example INSERT into Xinhuazidian (A, B, c) VALUES (' AAA ', ' BBB ', ' lao8.org '), (' Aaa2 ', ' bbb2 ', ' m.lao8.org ') on DUPLICATE key update

If the on duplicate key update is specified at the end of the INSERT statement, and DUPLICATE values appear in a UNIQUE index or primary key after the row is inserted, the old row UPDATE is executed; if the unique value column is not duplicate, a new row is inserted. For example, if column a is defined as UNIQUE and contains a value of 1, the following two statem

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 1Copy codeThe Code is as follows:Delete YourTableWhere [id] not in (Select max ([id]) from YourTableGroup by (name + value ))Method 2Copy codeThe Code is as follows:DeleteFrom table a left join (Select id = min (id) from Table group by name, value) B on a. id = B. idWhere B. id is null SQL statement for querying and deleting

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 = min (ID) from Table group by name, Value) B on A. ID = B. IDWhere B. ID is null SQL statement for querying and deleting duplicate recordsS

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. duplicate records are determined based on a single field (peopleId ). select * from people where peopleId in (select peopleId from people group by peopleId having count(peopleId) > 1)

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. Search for duplicates Recording 1. Search for all Repeated Records Select * from table where repeated field in (select repeated field from Table group by repeated field having count (*)> 1) 2. Filter

SQL statement for querying and deleting duplicate records 1. Search for redundant duplicate records in the Table. duplicate records are determined based on a single field (ID ). Select * from table where ID in (select ID from Table group byid having count (ID)> 1) 2. Delete unnecessary duplicate records

How to remove duplicate data from an Oracle database. When you use a datasheet, you often get duplicate data, so how do you delete it? The following green Tea Small series for you to share the resolution of Oracle database data duplication problem. Oracle database duplication of data generally have two ways to weight, one, complete duplication of data, two, some of the field data duplication to heavy. a c

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 a similar experience, when querying or statistics of the database will occasionally encounter due to the existence of duplicate records in the table resulting in inaccurate query

Tags: title max repeat record ROWID delete ROM using statement casehttp://blog.csdn.net/anya/article/details/6407280/With SQL statements, delete duplicates only keep one 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 are based on a single field (Peopleid) to determineSELECT * from Peoplewhere Peopleid in (select Peopl

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 0 Method Two There are two duplicat

Using on DUPLICATE KEY update Look at two SQL first The code is as follows Copy Code INSERT into Osc_visit_stats (stat_date,type,id,view_count) VALUES (?,?,?,?) On DUPLICATE KEY UPDATE view_count=view_count+? Osc_visit_stats table has composite primary key (Stat_date,type,id) Multi-field Update The code is as follows Copy Code INSERT into