MySQL

First, mathematical functionsABS (x) returns the absolute value of XBIN (x) returns the binary of X (Oct returns octal, HEX returns hex)CEILING (x) returns the smallest integer value greater than XEXP (x) return value E (base of natural logarithm) x

Permission to change or delete the searchGrant Select on testdb.* to [email protected] '% 'Grant Insert on TestDB. * to [email protected] '% 'Grant Update on TestDB. * to [email protected] '% 'Grant Delete on TestDB. * to [email protected] '% 'Grant

1, Connection MySQL format: mysql-h host address-u user name-P user Password1. Connect to MySQL on this machine. First open the DOS window, then enter the directory Mysql\bin, and then type the command Mysql-u root-p, enter after the prompt you to

Recently used MySQL master and slave, see this article, take out to share a bit.Turn from: http://www.cnblogs.com/kerrycode/p/4364465.html Xiaoxiang Hermit　RPM Package Installation method MySQL Uninstall1: Check if the MySQL component is installed.[[

We need to use the MySQL alter command when we need to modify the data table names or modify the field of the data tables.Before starting this tutorial, let's create a table with the table named: Testalter_tbl.[Email protected]# mysql-u root-p

In the MySQL source code directory, the SQL directory is one of the most frequently-changed directories in MySQL sources, and is also the core and important directory of the MySQL server kernel. In addition to the file containing the MySQL main

Data Sheet A data table (or table) is one of the most important components of a database and is the foundation of other objects.First to solve the problem of entering database validation at the end of the last blog post:Verify which MySQL command is

/* Index *//* Index design principles 1. Try to choose a uniqueness index of 2. Order by,group by,distinct for frequent needs, The field of the Union is set at index 3. Sets the index for a field that is commonly used as a query condition 4. Limit

This article mainly describes the CentOS 6.4 configuration Lnmp Server detailed steps, the need for friends can refer to the followingPrepare the article1, configure the firewall, open 80 ports, 3306 portsVi/etc/sysconfig/iptables-A input-m

when you insert a table a data, insert B table of data need to add corresponding to the corresponding field in a table of the self-increment, how will you get to the a table of self-increment? You may not know the self-increment in MySQL. four ways

For the software development is actually in the fact that it is constantly working with the data, so the operation of the database is essential, the next introduction of VC development using ADO to establish an ODBC data source to access the MySQL

Change the sales status of April 20 to the current time period to unsold (1), the sales time to null (0) UPDATE hy_car_detail hcd SET hcd.sales_date = ", Hcd.sales_status = ' 1 ' where HCD . car_id in (Select hc.car_id from Hy_car HC WHERE

MySQL sub-table method:Method One, do the database cluster! Master-Slave database bidirectional hot backup (or one-to-many database real-time backup strategy), which can allocate database queries to several servers (can be combined with server load

One: OverviewCompared with other databases, MySQL's locking mechanism is relatively simple, and its most notable feature is that different storage engines support different locking mechanisms. For example, the MyISAM and memory storage engines use

Binary installation is actually already compiled MySQL, do a compressed package, download down, unzip, simple configuration, you can use, ' install ' fast, often used for rapid deployment of MySQL.To add a MySQL user:[[email protected] ~]# groupadd

If the file system is damaged or accidentally deleted the database files, as long as the disk space is not overwritten, the data is still in the disk sector, or can be recovered, some common file recovery tool seems to be able to recover files, but

The main contents are as follows:1. How to connect a database2. How to operate the database(1) How to execute SQL language(2) How to process the returned result setMethod One: Process oriented (obsolete, just understand)Assume:1 $username =your_name;

There are a lot of basic commands in MySQL, and the show command is one of them, and it's easy to confuse the use of SHOW commands among many users, and this article brings together the many uses of the show command.A. Show tables or show tables

SQL: insert all other columns of rows with the same primary key updated. In SQL writing, we often encounter such problems. During each insert operation, you must determine whether the data table already exists. For the same data, all the columns

Mysql master-slave backup and SQL statement backup, mysql master-slave SQL statement The master-slave configuration of the MySQL server is a very simple task. Instead of starting from scratch, it is always on the mysql server that has been installed