MySQL

Mysql> query statement * query multiple unique records with id 1 a 2 B 3 c 4 c 5 bselect id, name from s1 group by name1 a2 b3 c5 B * query records with the most repeated records SELECT keyword, count (*) AS count FROM article_keyword group by

The same server MYSQL master-slave configuration installs two MYSQL services on one server, and configures master-slave management of the MYSQL service. (1) modify the my. ini file (master ). Add log-bin = E: /MySqlData/mysql-bin // location of the

Preparations for the mysql replication official Chinese documents: 1. Ensure that the mysql versions on the Master and Slave hosts are consistent to avoid unnecessary troubles. 2. Ensure that the Master/Slave can ping each other and communicate with

Mysql5 insertion garbled problem in the database upgraded from 4.2 to 5.1.6-comm... latin1 is followed by the default encoding. Chinese characters are garbled in previous programs. The previous method is to add charset = gb2312 to source, and then

MySQL5.5 stored procedures support limit VariablesWhen reviewing the developed SQL statements, they found a stored procedure that was pieced together with a dynamic SQL (CONCAT () function). In this way, the performance was not as good as static SQL,

Mysql statistics retention rate SQL code begin declare I int; declare numareaId int (10); declare currentareaId int (10); SELECT COUNT (areaId), MIN (areaId) INTO @, @ B FROM option_area_info; SET numareaId = @ a; SET currentareaId = @ B; loop1:

Do not modify a column of statements in the database to prevent ROPTRIGGERIFEXISTS 'userinfo' from being written into the name, age, tel, fax and other fields in the userinfo table; SET @ OLD_ SQL _MODE = @ SQL _MODE, SQL _MODE = ''; DELIMITER //

Using indexes in mysql to create indexes for tables is undoubtedly one of the best Optimization Methods for databases. The following is a summary of the index. Mysql query Optimizer's choice of indexes 1. Even if one SQL statement can select

Research on mysql "group by" and "order by" -- the latest content in classificationThese two days make it difficult to query a data. The main reason is that the understanding of group by is not deep enough. This is the case.I think many people have

Mysql Backup and recovery tuning Mysql Backup and recovery mysqldump, ibbackup, replication Backup points: Hot Backup (Hot Backup) online Backup, no impact on the DB when Cold Backup (Cold Backup) is stopped, simple: Copy physical files, offline

MySQL 5.5 permission export script [plain] #! /Bin/sh base_dir = '/opt/soft/mysql' mysql_user = 'root' mysql_pwd = '000000' mysql_socket = '/tmp/mysql. sock 'msyql_grants = '/tmp/mysql_grants. SQL' result = '$ {base_dir}/bin/mysql-u $ {mysql_user}-p

The following article describes how to create and delete a MySQL trigger. If you create a MySQL trigger correctly, if you are interested in deleting the MySQL trigger, you can click the following article to view it. 1. CREATE a MySQL TRIGGER. Syntax:

The mysql index length tips innodb and myisam engines fail to create tables in the production environment due to issues such as the developer's lack of understanding or neglect of indexes and different versions. Summarized the test environment mysql>

Linux daemon & mysqld is not strictly speaking. daemon is a service and can be divided into two categories: ① stand alone ② super daemon is not strictly speaking, the corresponding port of the service, that .... then, daemon corresponds to the port .

Shell to operate mysql database mysql-hhostname-Pport-uusername-ppassword-e related mysql SQL statements, you can operate mysql in shell without running mysql at a mysql prompt. #! /Bin/bash HOSTNAME = "192.168.111.84"; # Database Information PORT =

MySQL performance computing ##################################### ######################################## ##### QPS (Queries Per Second): mysql> show /*! 50000 global */status like 'questions'; mysql> show /*! 50000 global */status like 'querys';

ERROR 1820 (HY000) occurs during mysql installation: You must set password before executing this statement solves the problem that the newly installed mysql always has an ERROR prompt when it enters the mysql tool: # mysql-u root-pEnter password:

Compile and install mysql in Debain. 1. Make sure you are ready to install the binary file... # (if you provide your own files, be sure not to make the version wrong) wget

Mysql has a large number of sleep processes and solutions. mysql server has a large number of sleep processes. This article analyzes the causes and solutions for the large sleep process in mysql. Possible cause: why are there too many sleep

MySQL reserved keywords today, when we use hibernate to associate ing to export tables, because a table named option is mapped to a MYSQL keyword, errors are always generated. At first, we thought it was a ing file and code problem, the reserved