MySQL

1.unix_timestampConverts a time into a timestamp. (date type data converted to timestamp form integer)Time stamp of the current time without passing the time parameterMysql> select Unix_timestamp ();+------------------+| Unix_timestamp () |+---------

Ext.: http://blog.sina.com.cn/s/blog_1512521570102wrfl.htmlSelect Cost,@a:[email protected]+1 from Testone, (select @a:=0) as A;The variables in MySQL do not have to be declared beforehand, use "@ variable name" when using it.First usage: Set @num =

MySQL Optimization Topic Development--Wang YaoyuFirst, SQL Optimized1. Analysis and positioning strategies1. Learn the frequency of SQL execution through show status2, location execution inefficient SQL statement: ① through slow log positioning; ②

Problem background Description: Execute SQL statements in MySQL, such as insert, thief slow, obviously may be just a row of data inserted, the amount of data is very small, but the time spent is many, why?First, storage structure analysisMySQL

Drbd+heartbeat + LVS + keepalived+ MySQLHardware: Master *: Install DRBD, Heartbeat,mysqlSlave*3: Installing MySQLKeep Alived Host * 2: Install LVS, keepalived (real server is slave)Application HostIP: Two master has an ha VIP1Two keepalived hosts

First, SQL Optimized 1. Analysis and positioning strategies1. Learn the frequency of SQL execution through show status2, location execution inefficient SQL statement:① through slow log positioning; ② use the show processlist command to view the

In the MySQL tool search or insert data times under Error: Error 1055 (42000): Expression #1 of SELECT list is not in GROUP by clause and contains Nonaggreg ated column ' Database_tl.emp.id ' which is not functionally dependent on columns in GROUP

Set MySQL passwordSET PASSWORD = PASSWORD (' [email protected] ');Setting up a MySQL remote connectionGRANT all privileges on * * to ' root ' @ ' 192.168.4.0 ' identified by ' [email protected] ' with GRANT OPTION;Forgot MySQL PasswordUPDATE

Large web site in order to soft solution a large number of concurrent access, in addition to the site to achieve distributed load balancing, far from enough. To the data service layer, the data access layer, if the traditional data structure, or

#!/bin/bash#Date: 2017-04-21#Author: Allen_jol#mysql -5.6.17_v2.0#卸载自带的mysql-libsRPM-E--nodeps Mysql-libs#安装所需软件依赖Yum-y install make gcc gcc-c++ ncurses ncurses-devel pcre pcre-devel zlib zlib-devel OpenSSL openssl-develMdir=/usr/local/srcCD $MDIRLS

The MySQL system variables include global variables (globals) and session variables (sessions), the global variable takes effect for all session, and the session variable includes the global variable. MySQL tuning is bound to involve the adjustment

First, B-treeB-tree is the most common type of index, and all values (columns indexed) are ordered, with each leaf node being equal to the distance from the node. So B-tree is suitable for finding data in a range and can directly support data

[[Email protected] etc]# service mysqld startStarting MySQL .... The server quit without updating PID file[failed]/lib/mysql/ip12189.pid).Reason:Using the Default-character-set setting in Mysqld, mysql boot will be error-enabled.5.1 version, you can

Due to the configuration of Zabbix monitoring, a day received Zabbix monitoring master-Slave Alarm, view the MySQL status,Showslave status \g;SLAVE replication status is incorrect, slave_sql_running is no,Then look at the following error message,

1. Install wget commandYum-y Install wget2, can also directly copy 64-bit, through the command download: wget http://dev.mysql.com/get/Downloads/MySQL-5.6/mysql-5.6.33-linux-glibc2.5-x86_64.tar.gz3.Unzip TAR-ZXVF

An error occurred while using the Concat connection string: MySQL Error:illegal mix of collations for operation ' Concat '　　cause : The Field Operation defaults to UTF8 encoding, which should be used for absolute uniform use of UTF-8, while other

：Https://dev.mysql.com/get/Downloads/MySQL-5.7/mysql-5.7.18-linux-glibc2.5-x86_64.tar.gz about 600M can choose Thunder Download and then upload, Because it is intranet, I choose Thunder Download.1. Download:[Email protected] ~]# wget

Add, query, modify, and delete Mysql tables, columns, and databases Below are some basic SQL knowledge I have summarized, mainly to better check and help other beginners and record their own growth in the future, I also wrote some SQL interview

Common mysql optimization methods and common mysql Optimization Methods 1. select an appropriate field attribute. For exampleDefine zip codeWhen this field is set to CHAR (255), it obviously adds unnecessary space to the database, and even uses the

ProxySQL read/write splitting and proxysql read/writeFirst, let's take a look at our environment:MHA has been set up: master：172.16.16.35:3306slave：172.16.16.35:3307slave：172.16.16.34:3307 MHA manager is located at 172.16.16.34. The configuration