MySQL

MySQL federated queries are more efficient, with the following examples to illustrate the benefits of federated queries (inline, leftist, right-click, full-Union):T1 table structure (user ID, user name, password)UserID Username Password1 Jack

Describes some of the common MySQL monitoring tools. Cacti Cacti is a set of graphical analysis tools for network traffic monitoring based on PHP,MYSQL,SNMP and RRDtool development. It uses Snmpget to get data, use RRDtool to draw

prepare the article: 1, configure the firewall, open 80 ports, 3306 portsVi/etc/sysconfig/iptables-A input-m state--state new-m tcp-p TCP--dport 80-j ACCEPT #允许80端口通过防火墙-A input-m state--state new-m tcp-p TCP--dport 3306-j ACCEPT #允许3306端口通过防火墙 Note:

Test the connection condition:"1045-access denied for user ' [email protected] (using Password:no)" will appear if the remote login user is not added to the permissions that all machines can access, which indicates the need to add permissions;Add

First, let's talk about why the tables are divided.When a piece of data reaches millions of, you spend more time searching for it, and if you have a joint query, I think it's possible to die there. The purpose of the sub-table is to reduce the

MySQL Date time function encyclopediaDAYOFWEEK (date)The return date is the day of the week (1= Sunday, 2 = Monday,...... 7= Saturday, ODBC Standard)Mysql> Select DAYOFWEEK (' 1998-02-03 ');3WEEKDAY (date)The return date is the day of the week (0=

Each of the two fields that are foreign keys must be primary keys Two tables must be a InnoDB table,MyISAM table temporarily does not support foreign keysThe columns of the two tables of the foreign key relationship must be of similar data types,

Retrieves a list that does not already have the same value, plus the DISTINCT keywordSELECT DISTINCT vend_id from Products;You can limit the number of returned results by using the limit clauseSELECT Prod_name from Products LIMIT 5;The limit clause

Here's a brief look at MySQL's use of regular expressions when filtering data, primarily for each usage, or to add a few short notes.This is to say in advance that using regular expressions to filter the data is using the REGEXP keywordBasic

one, key and primary key differenceCREATE TABLE Wh_logrecord (logrecord_id Int (one) not NULL auto_increment,User_name varchar (+) default NULL,Operation_time datetime default NULL,Logrecord_operation varchar (+) default NULL,PRIMARY KEY

Many students in the Web site, the first is in the local environment to make the site, and then through the site to move to the site space, this practice is very good, but also bring some unforeseen problems.If the DZ Forum can not upload avatar is

Original address: http://www.cnblogs.com/gomysql/p/3671896.html, tribute to the original author YayunBrief introductionMMM (Master-master Replication Manager for MySQL) is a set of scripting programs that support dual-master failover and dual-master

Recently read the O ' Reiliy series of "high-availability MySQL", naturally without the master-slave (master-slave) configuration and scale-related content. Master-slave this thing, in many companies are standard, the development of the basic daily

MySQL mysqldump Export only table structure does not export data The code is as follows:Mysqldump--opt-d database name-u root-p > Xxx.sql backing up the databaseThe code is as follows:#mysqldump database name > Database backup name #mysqldump-A-u

MySQL's cast () and CONVERT () functions can be used to get a value of one type and produce a value of another type. The specific syntax for both is as follows:View Source print? 1 CAST(value astype);

First, the environmentMaster (Host a): 192.168.1.1Slave (Host B): 192.168.1.2W-VIP (write): 192.168.1.3R-VIP (Read): 192.168.1.4Client (test): 192.168.1.100Operating system version: CentOS release 6.4MySQL database version: 5.6.14Keepalived version:

To create a table and insert a data statement:Mysql> CREATE TABLE salary (userid int,salary decimal (9,2));Query OK, 0 rows affected (0.11 sec)Mysql> INSERT into salary values (1,1000), (2,2000), (3,3000), (4,4000), (5,5000), (1,NULL);Query OK, 6

Install MYSQL and osmysql on MAC OS X I found an article on the Internet, which is really an artifact. You can find it at the beginning by using brew search mysql... and follow the prompts to install it step by step. The final result is that it

Mysql automatic backup, using MD5 for unique backup1. Name the backup database temp. SQL and calculate its MD5 value (for MD5 calculation method, see MD5.java) String dos = "cmd/c mysqldump-uroot-pwugroup weixin> D:/mysql_back/temp. SQL "; //

MySQL "replace into", mysqlreplaceinto MySQL has many extensions for SQL, some of which are very convenient to use, but some may have performance problems after misuse, and some unexpected side effects, such as REPLACE. For example, there is a table: