mysql delete duplicate rows but keep one

Delete duplicate records in a table, leaving only one entry:Delete from where inch (Select* from,selectmaxfromgroup by having Count > 1 as B);Instance:2. When you want to create a unique index for a table, you need to delete duplicate records

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,

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

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

This article is a MySQL database insert, UPDATE, delete and replace statements in the use of detailed analysis of the introduction, the need for friends to refer to the MySQL database insert and UPDATE statements Introduction: The SQL used to

MySQL database insert and UPDATE statementsIntroduction: The SQL used to manipulate the database is generally divided into two kinds, one is the query statement, that is, we call the SELECT statement, the other is to update the statement, also known

Let's look at the following example: 1 Replace into ...1.1 Input raw Data mysql> use test; Database changed Mysql> mysql> CREATE TABLE T1 SELECT 1 as a, ' C3 ' as B, ' C2 ' as C;ALTER TABLE T1 Change a a INT PRIMARY KEY auto_increment;Query OK,

1. Export the entire database Mysqldump-u user name-p--default-character-set=latin1 Database name > exported file name (database default encoding is latin1) Mysqldump-u wcnc-p SMGP_APPS_WCNC > Wcnc.sql 2. Export a table Mysqldump-u user name-P

The SQL used to manipulate the database is generally divided into two types, one is the query statement, which we call the SELECT statement, the other is the UPDATE statement, also known as the data manipulation statement. The implication is that

"Common interview questions Summary catalogue >>>"091 Database Deadlock ConceptIn most cases, it can be assumed that if a resource is locked, it will always be released at a later time. Deadlocks occur when multiple processes access the same