mysql find duplicate values

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

MySQL prevent duplicate Insert Record method summaryThere are many ways to prevent MySQL from repeatedly inserting records, usually Ignore,replace,on DUPLICATE KEY UPDATE, which we can also judge in PHP.Scenario One: Using the Ignore keywordIf the

Sometimes a table or result set contains duplicate records. Sometimes it is allowed, but sometimes it needs to stop repeating records. Sometimes it needs to recognize that duplicate records are removed from the table. This chapter describes how to

In the previous article, we mentioned two ways to INSERT and process duplicate key values in MySQL: replace into and insert into on duplicate key update, today, we will introduce the ignore into method for implementing MySQL insertion and processing

Scenario One: Using the Ignore keyword If the uniqueness of the record is distinguished by the primary key primary or unique index unique, it is possible to avoid duplicate insertion records: The code is as follows: The code is as

The examination system has done a user to import the question function, causes the user to import many duplicate questions, I need to inquire and deletes the duplicate record, therefore has this article. (i) a single field 1, look up the redundant

If you like these articles, click here to subscribe to this BlogMySQL Method for querying and deleting duplicate records (1) 1. Find excess duplicate records in the Table. duplicate records are based on a single field (peopleId) select *

My WordPress database Wp_postmeta table has more than 10,000 lines, if the use of two cycles to find the judge, although we are not tired, but the program runs very tired AH. If I want to query with a single statement to get all the data that

Mysql auto-incrementing column leads to duplicate primary key issue analysis..., mysql primary key A few days ago, the development of shoes reported a problem of using the load data infile command to import data primary key conflicts. After analysis,

(i) a single field 1, look up the redundant records in the table, according to (Question_title) field to judge The code is as follows Copy Code SELECT * from questions where Question_title in (select Question_title to