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This article describes how to use the MIN () function in MySQL, you can refer to the MySQL MIN function to find the minimum value of a record set. The EMPLOYEE_TBL table for MIN functions has the following records: mysql> SELECT * FROM

This article describes how to delete a table in MySQL. it is the basic knowledge in MySQ learning. it is easy for anyone who needs to discard a table in MySQL. However, you must be very careful when deleting any existing table and cannot recover it

This article mainly introduces the knowledge of NULL values in MySQL, which is the basic knowledge in MySQL beginners, for more information, see the SQL SELECT command of the WHERE clause to obtain data from the MySQL table. However, when the

This article describes how to create a MySQL database. Use mysqladmin to create a database: Special permissions are required to create or delete a MySQL database. Therefore, if you access the database as a root user, you can create any database

This article describes how to use the ADDDATE () function in MySQL. it is the basic knowledge in MySQL getting started. For more information, see the following code: ADDDATE (date, INTERVAL expr unit), ADDDATE (expr, days) When the second

This article describes how to view the space occupied by data tables and the number of records in the MySQL database. if you want to know the space occupied by each table in the MySQL database and the number of rows recorded in the table, you can

This article describes how to use the RAND () function in MySQL. it is the basic knowledge in MySQL beginners. if you need it, refer to MySQL RAND () function calls can generate a random number between 0 and 1: mysql> SELECT RAND( ), RAND( ), RAND(

This article describes how to use the AVG function in MySQL to calculate the average value, you can refer to MySQL's AVG function to find the average value of fields in various records. For more information about the AVG function, consider that the

This article mainly introduces how to implement batch insert in MySQL to optimize performance. This article provides a comparison of running time to indicate performance optimization, if you need a database, you can refer to some systems with a

This article describes how to use GTIDs replication protocol and interrupt protocol in MySQL. it is mainly used for communication between multiple servers. For more information, see MySQL5.6 which has many new features, most people are interested in

This article mainly introduces some practical cases of MySQL index optimization, mainly using the OrderbydescasclimitM method, for more information, see Order by desc/asc limit M. It is a scenario that I often encounter in mysql SQL optimization.

This article mainly introduces some of the optimization straight_join techniques in MySQL. based on the user's actual case analysis, you can refer to the hint of table join that can be specified in oracle. There are many: ordered hint indicates that

This article mainly introduces several suggestions for reducing MySQL disk space, mainly from two aspects: table structure and storage content, for more information, see TPS \ QPS of some customers. However, the disk usage is very large, such as

By default, when the idle time of a connection exceeds 8 hours, MySQL disconnects the connection, and the c3p0 connection pool assumes that the disconnected connection is still valid. Assume that your database is mysql. if the data source is

This article mainly introduces how to generate a backdoor Trojan using Mysql statements. do not destroy it at will. you can just study it. Ke, let's take a look. I am not responsible for the consequences. SELECT * FROM 'vbb _ strikes 'WHERE 1

This article describes how to obtain slow log information by time in MySQL. the tool cutlogbytime is used to set the timestamp. For more information, see the following example: the database is abnormal and the number of connections suddenly

This article mainly introduces four methods to kill MySQL connections in batches. This article provides code examples. For more information, see Method 1 Use the connection information in the information_schema.processlist table to generate a

This article describes how to obtain the last record of each userid in a MySQL table. if the userid is not unique, you can refer to the following table: CREATE TABLE `t1` (`userid` int(11) DEFAULT NULL,`atime` datetime DEFAULT NULL,KEY

This article mainly introduces how to improve the storage efficiency of BLOB columns in InnoDB tables in MySQL. InnoDB optimization is also a hot topic in MySQL optimization research, for more information, see the following: 1. InnoDB supports the

This article mainly introduces the notes for using the DATE_FORMATE function in MySQL. it mainly describes the need to convert its built-in character set for use, for more information about how to handle an SQL statement (simplified), see the