MySQL

When migrating a database from MSSQL to MySQL, You need to insert 0 values in the auto-increment column of MySQL based on the requirements of business logic. In MSSQL, this is done as follows:Copy codeThe Code is as follows:String SQL; SQL = "set

MySQL log Files are generally stored in/var/log/mysqld. log. The following describes how to modify the location of MySQL log files for your reference.Today, you need to change the location of the MySQL Log File and find that it cannot be changed

When creating a table, we will inevitably consider the disadvantages of weeks. Therefore, we need to use the alter table statement to modify the table later.Modify Table Name Copy codeThe Code is as follows:Mysql> alter table student rename

In the past few days, I have learned how to optimize the mysql database and set it on my own server. I have learned how to optimize the MyISAM and InnoDB engines. They have their own advantages and disadvantages, generally, it is better to combine

The Default value of timestamp is Default CURRENT_TIMESTAMP.The timestamp is set to automatically update on update CURRENT_TIMESTAMP as the table changes.HoweverA table can have at most one field set CURRENT_TIMESTAMPYou cannot set DEFAULT

This article introduces some commonly used mysql commands for data import and export. As long as we hold these commands, we can quickly back up and restore the database.Import and Export mysql Data to MBProblem: the database and table data of MB

However, after VPS is involved, it is not just about backing up MySQL, but also about backing up some independent site data.If there is a reliable third-party Linux host or cloud storage like Amazon, it is much simpler, and Linux-Linux backup is

Comparison of not in, JOIN, is null, not exists EfficiencyStatement 1: select count (*) from A where A. a not in (select a from B)Statement 2: select count (*) from A left join B on A. a = B. a where B. a is nullStatement 3: select count (*) from A

Copy codeThe Code is as follows:Delimiter |Drop function if exists IS_MOBILE |Create function IS_MOBILE (x VARCHAR (255) returns tinyint (1)BEGINDECLARE result TINYINT (1) DEFAULT 0;SET x = LCASE (x );If right (x, 4) = '.mp4 'THENSET result =

Syntax format:EXPLAIN tbl_nameOr:Explain select select_optionsThe EXPLAIN statement can be used as a synonym for DESCRIBE, or used to obtain information about the SELECT statement to be executed by MySQL.The EXPLAIN tbl_name syntax is the same as

Method 1Phpmyadmin is the simplest. Modify the user table of the mysql database,But don't forget to use the PASSWORD function.Method 2 Use mysqladmin, which is a special case stated above.Mysqladmin-u root-p password mypasswdAfter entering this

In addition to the index of different table names, the table structure is the same. If the 'id' field of each table still adopts the 'Auto _ INCREMENT 'method, ID cannot identify only one record.In this case, an External table shard mechanism is

In the architecture of Apache, PHP, and MySQL, MySQL has the greatest impact on performance and is also a key core component. For Discuz! The same is true for Forum programs. Whether MySQL settings are reasonably optimized directly affects the speed

In database optimization, it is one of the most common and effective methods to minimize the data size and minimize the space occupied by tables on the hard disk. Because of data reduction, the read/write speed of the hard disk can be improved, and

Although many GUI-based MySQL clients exist, such as the famous phpMyAdmin and SQLYog, I have always liked the native MySQL command line client. Indeed, I am not familiar with these command line interfaces (CLI) previously, it took us some time to

In a recent project, you need to perform fuzzy search for multiple keywords in a single MySQL table. However, these keywords do not necessarily exist in a field. For example, in an existing table, there are three fields: title, tag, and description,

To prevent security risks, we generally set an independent database access account for each database. This account has only the permission to access the database. Here is a detailed demonstration: 1. First, we need to log on to phpMyAdmin without

Outer Join. Outer Join can be left Outer Join, right outer join, or complete external join.When an external join is specified in the FROM clause, it can be specified by one of the following sets of keywords:Left join or left outer join.The result

1. Connect to MYSQL. Format: mysql-h host address-u user name-p User Password 1. Connect to MYSQL on the local machine. First, open the DOS window, enter the mysql \ bin directory, type the mysql-u root-p command, and press enter to prompt you to

The problem is as follows:A test table. The character set uses latin1.Select to_id from test where to_id = 'cn elephant _ Wang ';+ --------------- +| To_id |+ --------------- +| Cn Tao _ Tao || Cn xiang_wang |+ --------------- +2 rows in set (0.00