MySQL

This is my first day in Beijing University high-tech company. "The first week to self-study mainly to adapt to current javaweb development mainstream technology, so to develop a program demo as the first week of the task schedule.Mission Objective:

MySQL Replacement stringThe Replace function in MySQL directly replaces a specific string in a field in a MySQL database, eliminating the need to write a function to replace it, which is very handy. MySQL Replace function replace ()UPDATE table_name

Integrating system is being developed! One of the data is to show the user points ranking?I can't think of such a good way!The simplest scenario is to unify the ranking of a field's points data? such as the integral field, the integer stored

Mysql> SHOW GLOBAL STATUS like ' innodb%read% '; +---------------------------------------+---------+| variable_name | Value |+---------------------------------------+---------+| Innodb_buffer_pool_read_ahead_rnd | 0 | | Innodb_buffer_pool_read_ahead

It's also a small problem. But small problems also need time to solve. It's not good to deal with it. There are also tutorials online. But always remind yourself that your brain is alive. Can't copy.1 The cause of the problem, a project of the

Code pay Payflag00001 100.00 000001 50.00 100001 50.00 000002 200.00 0Pay is Decimal,payflag 0 is Payment, 1 is a refundAdd the same code and payflag=0 pay minus payflag=1 pay to get the following dataCode pay00001 100.0000002 200.00The first

I this broken notebook slow to die, today and re-install system, God horse East software to reload again (:-O), decisive first virtual machine to catch first ^ ^, re-installed lamp.MySQL source installation steps are as follows:1: Because it is a

1. What is a subquery?In layman's words, there are queries in the query, and there are multiple SELECT statements in the SQL statement.2. Where can I embed a subquery?SELECT column (not within the standard)From table (can be embedded, exists as a

A transaction (Transaction) is a program execution Unit (unit)that accesses and possibly updates various data items in a database. Transactions are the basic unit of recovery and concurrency control. In a relational database, a transaction can be

I do not use the database graphics operating software, with the terminal directly manipulate databases and tables.First, the database : Login database system: mysql-h hostname-u user name-P, press "enter" to display "Enter Password", enter

1. may be/usr/local/mysql/data/rekfan.pid file does not have permission to writeWorkaround: Give permission, execute "chown-r mysql:mysql/var/data" "Chmod-r 755/usr/local/mysql/data" and restart mysqld!2. The MySQL process may already exist in the

Version: MySQL official website, download the win7-64-bit MySQL server installation package.Decompression: C:\Program files\mysql\mysql-5.6.25-winx64.Configure environment variables: Mysql_home=c:\program files\mysql\mysql-5.6.25-winx64, add to Path:

0. DescriptionMySQL service version best consistent, inconsistent may cause problemsmaster database ip:192.168.0.10Slave database ip:192.168.0.111. Modify Master server Mastervi /etc/my.cnf[mysqld]log-bin=mysql-bin #[must be] enable binary log

The InnoDB engine differs from the MyISAM engine. MyISAM InnoDB row-level lock non-object security things security full-text indexing full-text

Nothing, two weeks ago. The results of the import and export of MySQL are now forgotten again.It is even more tragic that the same three blog, now looks like the same strenuous, the contents of the inside. So write a note for yourself.Environment:

MySQL master-slave switchMaster stop, from the bossThe steps are as follows:1 Confirm that all synchronization operations have been completed from the server:Stop slave Io_threadShow ProcesslistUntil you see the status: XXX has read all relay log

Mysql bit operation 1. MOD (X1, X2) calculates the remainder and returns the same remainder as "%" 2. X1 DIV X2 returns the operator for Division. The same as "/" 3. If the divisor is 0, the result is NULL. 4. and = are the same. They are used to

MySQL delayed Index Update (delay_key_write) MySQL Delayed Index Update (Delayed Key Write ): The myisam Table created using the table creation option DELAY_KEY_WRITE will not write the index change data to the disk after the query ends, but will be

Use of MySQL ViewOverview: A view is a virtual table, also known as a derived table, because its content is derived from the query results of other tables. Although the view looks like a basic table, they are not basic tables. The basic table

Orderby Optimization-mysql The rder by keyword is optimized. We will analyze it today. First, let's take a look at the mysql official documentation on how to optimize the order by keyword. 8.2.1.15 order by Optimization The following statements use