delete duplicate records in sql

How to delete MySQL duplicate data: mysql duplicate data This example describes how to delete duplicate MySQL Data. Share it with you for your reference. The specific method is as follows: Project Background In a recent linux performance collection project, it was found that

Query and delete duplicate records of SQL statement 1, find redundant records in the table, duplicate records are based on a single field (ID) to determine the select * from table where

How to delete duplicate rows and duplicates in Excel2003 according to Delete duplicate rows 1. Position the cursor in the table, data-filter-Advanced filter. 2. Set the location where the filter results are placed and select the records that are not duplicat

The Oracle tutorial you are looking at is: Oracle quickly deletes duplicate records. When working on a project, when a colleague guides the data, he accidentally makes all the data in a table heavier, that is to say, there is a duplicate of all the records in this list. The data for this table is tens, and it is a prod

Ways to query and delete duplicate records1, look for redundant records in the table, duplicate records are based on a single field (Peopleid) to determineSELECT * from people where Peopleid in (select Peopleid from People GROUP by Peopleid have count (people ID) > 1)2,

Label:SELECT *From T_info AWHERE (SELECT COUNT (*)From T_infoWHERE Title = a.title) > 1)ORDER by Title DESC One. Find Duplicate Records 1. Find all duplicate records SELECT * FROM table Where repeating field in (Select repeating field from table Group by repeating field having Count (*) >1) 2. Filter

access| Repeat | repeat record There are duplicate records in one table, the number of repetitions may be one or more, how to leave only one in the duplicate records, delete other redundant records, so that each record of the data

As an Oracle Database developer or DBA, you often experience the problem of trying to create a unique index on a column or column in a library table, prompting ORA-01452: You cannot create a unique index and find duplicate records. Here we take table code_ref as an example to discuss this problem and its solution. Error is on line 1th: ORA-01452: Unable to CREATE UNIQUE INDEX; Find

A previous deletion of duplicate records although it's not bad, but when I met the heavy scale, I was too powerless to think of a new method. Thinking 1, keep the record of not duplicate 2. Save a ROWID in a duplicate record 3, delete the original table rowid is not rowid

to understand, the selection rules of exists or in should be the same in the subquery: the selection depends on the validity of the date and commodity conditions. Unless the business in the past six months is very light, the product name should be the most effective filter condition, so in is better than exists in subqueries. this is because, it is faster than the reverse operation to first find orders for all the bat vehicles and then check whether the sales have occurred in the last six month

Multiple statements for deleting duplicate records 1. delete all duplicate records (use with caution) delete table where duplicate FIELD in (select

1. Duplicate records can be identified by a single field: ID 1 and the name of ID 6SELECT * FROM student where name in (select name from student Group by name H aving COUNT(name) >1)In operator: Allows multiple values to be specified in the WHERE clause; GROUP by: Groups The result set by name; The Having:where keyword cannot be used with the aggregate function;Delete