MySQL

ORDER BYSort: It only makes sense after the result set is in the Where, group by, have afterDesc (Descending)/asc (ascending)Sort by fieldSort in descending order of Shop_priceSelect Goods_name,cat_id,shop_price from goods where cat_id=4 order by

[Email protected] ~]# Mysqldump-uroot-pmenglei discuzThis is the command to view the libraries backed up by the Discuz Library, mysqldump Backup tool, backup database, format and MySQL login is the same[Email protected] ~]# Mysqldump-uroot-pmenglei

Index type: B-tree index, hash indexThe B-tree index accelerates data access because the storage engine does not scan the entire table to get the data that is needed. Instead, it starts at the root node. The root node holds pointers to child nodes,

First, install the keepalived# Install keepalived Source Installation Dependency PackageYum-y install OpenSSL openssl-develyum-y install Popt-devel# Source Compilation installation keepalivedTar XF keepalived-1.2.7.tar.gz cd

The following is a detailed description of the issues that need to be noted in writing the WHERE clause of some SQL statements. In these where clauses, even if there are indexes on some columns, because poor SQL is written, the system cannot use the

MySQL Database optimization1. Query optimization(1) Avoid null values for fields in the WHERE clause(2) Avoid using or in the WHERE clause to join conditions(3) Less use like, if you want to consider full-text search(4) In No in also causes scan

1, MySQL four types of transaction isolation levelI. For running multiple transactions concurrently, when these transactions access the same data in the database, it can cause various concurrency problems if the necessary isolation mechanisms are

Method 1: Use the Set password commandMysql-u Rootmysql> SET PASSWORD for ' root ' @ ' localhost ' = PASSWORD (' Newpass ');Method 2: Use Mysqladminmysqladmin-u root Password "Newpass"If Root has already set a password, use the following

Linux installation MySQL--@ Beam WPSummary: Linux installs MySQL.First, download MySQL1, in Baidu Search MySQL, see one of the results is with MySQL downloads words, click into the website of MySQL.　　　　2, after entering the MySQL official website,

The following error occurred connecting to MySQL:ERROR 2002 (HY000): Can ' t connect to local MySQL server through socket '/tmp/mysql.sock ' (2)Thought the wrong place, the cache file exists under the TMPOn the Internet to check the cause of the

The Use command allows us to work with the database. Use command format: Use ;For example, if the XHKDB database exists, try to access it:mysql> use XHKDB;screen tip: Database changed1) The USE statement can advertise that MySQL uses the Db_name

In other words, this installation of MySQL is really twists, did not expect such trouble. I installed it with Yum Source and first provided some things to install MySQL with yum.Must be well equipped with Yum source, yum source problems can be

How do I get the nth data in a table?Can the limit statement return the first few data and a few rows of data in the middle,Mysql> SELECT * FROM table LIMIT 5, 10; Retrieving record lines 6-15In order to retrieve all the record rows from an offset

(1) First create the text file, (where created can) modify the suffix named Bat file, if your computer does not set the display suffix name, first by left click on My Computer, "view", "File extension", and so you have successfully modified the

#mysql version 5.4 is set to (better results in the following ways during testing):Innodb_read_io_threads = 12innodb_write_io_threads =6# If you find that the InnoDB tablespace is corrupted, setting this value to a value other than 0 may help you

1. Error code:1175 You is using Safe update mode and you tried to update a table without a WHERE thatFast and Efficient use: SET sql_safe_updates = 0; don't look at it!When you use MySQL Workbench to perform a database management update today, a

MySQL new features-mysql_config_editor source code analysisMysql has launched the encryption tool mysql_config_editor since mysql5.6. Previously, we put the account and password in plain text into my. cnf, so that you can log on to the database

[MySql learning experience], mysql learning experience 5. Common clauses in MySql 1. where clause We all know that when querying data, we may not be able to query the data in the entire table. When conditional queries are available, we will use the

Improve database schemaHibernate reads the ing metadata of your java model class and generates schemaDDL statements. You can export them to a text file, or execute them directly in the database when inheriting the test run. Because most database

[Mysql] about the checkpoint mechanism, mysqlcheckpointI. Introduction Think about this scenario: If the redo log can be infinitely increased and the buffer pool is large enough, you do not need to refresh the new version of the page in the buffer