mysql duplicate

How does MySQL process duplicate data? Some MySQL Data Tables may have duplicate records. In some cases, we allow the existence of duplicate data, but sometimes we also need to delete these duplicate data.This section describes how to prevent

This article summarizes the various SQL statements used to delete duplicate records in the mysql database. The following describes the operation methods with examples. For more information, see. This article summarizes the various SQL statements

MySQL replace into and on duplicate key update test notesMysql> CREATE TABLE tbl_insert_tmp (ID int (5), Addr_number Int (ten), name varchar, primary key (ID), unique key Udx_add R_number (Addr_number));Query OK, 0 rows affected (0.05 sec)Mysql>

This article refers to the link: http://blog.csdn.net/jbboy/article/details/46828917"I think the article is more suitable for learning and reference, it is worth a look"This article to provide you with three kinds of in MySQL to avoid repeated

This article to provide you with three kinds of in MySQL to avoid repeated insertion record method, mainly refers to the Ignore,replace,on DUPLICATE key update three methods, you can try to reference.Case one: Using the Ignore keywordIf the

MySQL database, often encounter duplicate records, then need to delete duplicate records SQL, the following list of four ways to delete duplicate records, for different situations, I hope to help you. 1, look for redundant records in the table,

There may be duplicate records in some MySQL tables, and in some cases we allow duplicate data to exist, but sometimes we also need to delete these duplicate data.In this section we'll show you how to prevent duplicate data from appearing in a

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

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

Related Articles: MySQL "on duplicate key update" Syntax Insert into .. on duplicate key to update multiple rows Http://dev.mysql.com/doc/refman/5.1/zh/sql-syntax.html#insert     MySQL "on duplicate key update" Syntax If the on duplicate key update