MySQL

Check out some MySQL commands in Linux: (Note: commands in the MySQL environment are followed by a semicolon as a command terminator)Remote connection command:Mysql-h 192.168.0.201-p 3306-u root-p123command to start MySQL: mysqladmin

It is possible for a program to know that the float type is a floating point number (that is, a decimal type), but there is a downside to float, and when the data you give is an integer, it is treated as an integer. So we have a natural problem

Pre-Optimization statements:SELECTIfnull (S.mileage,-1) as Mile,S.fuel_hkm as Val,T.fhkm_rank as Rank,Ifnull ((select U.photo from App_user u where u.user_id = t.user_id limit 1), ') as Path,case if s.car_id = ' *********** ' then 0Else 1 end as

First, pre-installation preparationInstalling the Epel sourceInstall wineIf you do not install wine, you may be unable to start after installing Navicat for MySQL.Second, install Epel sourceCd/tmpwget http://download.fedoraproject.org/pub/epel/6/i386

mysql> Stop slave;mysql> change master to master_delay=10; #单位是秒mysql > Start slave;mysql> show slave status\g* 1. Row *************************** slave_io_state:waiting for Master to send event ... Sql_delay:10

One, non-numeric type Type Range Description Char (N) [binary] n=1~255 charactersBinary: Distinguish case Fixed length Std_name Cahr (+) NOT NULL VarChar (N) [binary] n=1~2

Need to add the following in the configuration file okhttp://blog.csdn.net/zhq426/article/details/9787071/Tomcat links MySQL When the error Java.io.EOFException:Can not read response from server. Expected to read 4 bytes,

Http://www.cnblogs.com/xpchild/p/3825309.htmlOperations, often encounter auto_increment doubts: Machine exception crash, the issue of ID fallback after reboot Performance considerations, each acquisition is certainly not persisted,

The path to MySQL learning Directory MySQL Learning path "First article": MySQL single-and dual-instance installation MySQL Learning path "Second article": MySQL Log off, password modification hack MySQL Learning Road "third": MySQL

MySQL supports a very high number of data types, and choosing the right data type is critical to gaining performance.Several principles for choosing a data type1, smaller is usually better2, simple is good, such as using Date,time,datetime to store

--Mysql Database syntaxCreate DATABASE Database nameCREATE TABLE table name (ID int,name varchar (20));Copy tables and data the new table name after the CREATE table is copied select * from the old table name;Duplicate table structure CREATE table

Install the operating system first. Download the latest version of Ubuntu Linux dedicated MySQL on the MySQL official website. What I have downloaded here is: Mysql-server_5.7.11-1ubuntu14.04_amd64.deb-bundle.tar. The Unzip file command is:

MySQL encoding causes the database to appear garbled in ChineseWorkaround:Modifying the MySQL database character encoding for Utf-8,utf-8 contains the characters that are required for all countries worldwide and is an international code.Specific

Text: Ttt.txt Total 7,774,865 RecordsDisplay some of the text content as follows:"object_id", "object_name", "CREATED""A", "icol$", "2013/10/9 18:23:42""$", "I_user1", "2013/10/9 18:23:42""con$", "2013/10/9 18:23:42""All", "undo$", "2013/10/9 18:23:4

First, open the Binlog.First check to see if Binlog is turned onMysql> Show variables like "Log_bin", +---------------+-------+| variable_name | Value +---------------+-------+| Log_bin OFF +---------------+-------+1 row in Set (0.00 sec)The value

Problem Description:After the 1.mysql installation is complete, use theService mysqld StartAlways appears start failed.2. The/var/lib/mysql/mysql.sock problem cannot be found with Mysql-uroot-p login.3. Use the service mysqld status to appear MySQL

There are two ways to view the MySQL process1. Enter Mysqladmin processlist into the Mysql/bin directory;2. Start MySQL and enter show Processlist;If you have super privileges, you can see all the threads, otherwise you will only see the thread that

MySQL Replication is a very distinctive feature of MySQL, and he is able to copy the data from one MySQL server Instance to the Instance of another MySQL server. Although the replication process is not real-time but asynchronous, due to its

Today there is a requirement that MySQL multiple tables merge a table to find out how many userid (de-weight) the table has.First of all, my idea is to combine multiple tables with union into a single table, then groupby, and finally sum (userid)to

The basic process for MySQL master-slave replication is as follows:1. Slave the above IO line thread attached the Master, and requests the log content from the specified location (or from the beginning of the log) to the designated log file;2. When