MySQL

Create database mytest default charset = utf8 // create a databaseCreate table users // create a table(User_id int not null auto_increment,User_name varchar (20) not null,Description varchar (200 ),Primary key PK_userid (user_id));Show create table

Assume that the following N records indicate bookId author title1 aaa AAA2 bbb BBB3 ccc4 ddd5 eee AAANow I want to query all records with no duplicate titles from these five records.Select distinct title, author from book is not allowed because

First, add the login user permissions on the master server:Grant replicate slave on *. * to 'username' @ 'host' identified by 'Password'Set the my. ini file of the master server.Server-id = 1 # master server idLog-bin # enable binary

When you uninstall the old MYSQL Database Service from your computer, stop the MYSQL service in the WINDOWS service first. Go to the add and delete programs in the control panel to delete the MYSQL service. However, if you cannot completely delete

PhpMyAdmin was used for execution at the beginning, and a bunch of errors occurred later. begin was removed and can be executed normally after the end, but the stored procedure cannot be executed in phpMyAdmn, in the mysql command line text box, you

This is the button-Click Event on the page.Copy codeThe Code is as follows:Protected void button#click (object sender, EventArgs e){String tid = Utils. getRandom (32 );Stream mystream = this. FileUpload1.PostedFile. InputStream;Int length = this.

1. stop running mysql:/etc/init. d/mysql stop2. Use the skip-grant-tables option to start MySQL:/usr/bin/mysqld_safe -- skip-grant-tables &3. Now you can enter mysql without a password.# Myql> Use mysql;> UPDATE user SET password = password ('000000'

Because MYSQLDUMP adds a global lock for the entire database.If MYSQLDUMP is used for full-database backup, the following three factors may be affected.1. The server CPU is severely blocked.2. the disk I/O line is increased.3. All queries become

For example, table: event (id int (10) auto_increment primary key,Sid int (10) not null,Detail text) I want to delete records with duplicate sid in the event table. Is there such an SQL statement? Or through other methods?Copy codeThe Code is as

If you want to directly store binary data, such as image files and HTML files, in your MySQL database, this article is for you! I will show you how to store these files through HTML forms and how to access and use these files.Overview:. Create a new

In MySQL, some irrelevant records are often returned during fuzzy search of Chinese characters. For example, when searching for "% a %", Chinese characters may be returned, but no a character exists. I have encountered similar problems before. After

Rsync is used to configure a large number of mysql instances, saving a lot of time for compilation and configuration. After modifying my. cnf of the master and slave servers one by one, it is found that the data cannot be synchronized,On the slave

1005: An error occurred while creating the table.1006: database creation failed1007: the database already exists. An error occurred while creating the database.1008: the database does not exist. An error occurred while deleting the database.1009:

Solution 1: Use the ignore keyword If you use the primary key primary or the unique index unique to distinguish the uniqueness of a record, you can use the following to avoid repeated insertion of records: Copy codeThe Code is as follows:Insert

1GROUP_CONCAT Mysql>SELECT student_name,->GROUP_CONCAT (test_score)->FROM student->Group by student_name; Or: Mysql>SELECT student_name,->GROUP_CONCAT (DISTINCT test_score->Order by test_score desc separator '')->FROM student->Group by student_name;

Some netizens asked me how to automatically back up the MySQL database under win2003. Since it is an automatic backup, I must write a script. I thought, this is not very difficult, it is very easy to implement, backup can be implemented using

1. Check and modify the my. ini configuration file of mysql.Copy codeThe Code is as follows:Default-character-set = utf8 2. To create a database, you must specify the character set.Copy codeThe Code is as follows:Create database mydb default

1. Principle of master-slave synchronization latency in MySQL databases.To talk about the delay principle, we must start with the mysql database master-slave replication principle. mysql master-slave replication is a single-thread operation,The main

I. Purpose of backup Disaster recovery: recover and restore damaged dataDemand change: data needs to be restored to a time before the change due to demand changesTest: test whether the new function is available Ii. Backup considerations How long

I. SQL Mode SQL pattern matching allows you to use "_" to match any single character, while "%" matches any number of characters (including zero characters ). In MySQL, the SQL mode is case-insensitive by default. Some examples are shown below. Note