MySQL

  Readers who have studied database theory should still remember the Performance Comparison Between CHAR and VARCHAR: CHAR is faster than VARCHAR because CHAR is of a fixed length and VARCHAR requires a length identifier, an extra operation is

  MySQL provides a tool for importing and exporting databases. However, sometimes we only need to import and export data from a single table, such as importing and exporting CSV files. In this case, you can use the MySQL Automatic Command to import

  Lab 1 1. First, in the following situations: Mysql> show variables like 'character _ set _ % '; + -------------------------- + ----------------------------------------- + | Variable_name | Value | + -------------------------- + --------------------

I checked a lot of information and tried some. The final method is as follows: 1. Export mysql table definitions (no data)Mysqldump -- no-data [dbname]> dbdef. SQL 2. Use mysql2postgres to convert the script to pgsql 3. The script generated above is

Today, when connecting to mysql with myEclipse, the message "Communications link failure, Last packet sent to the server was 0 MS ago." error interface is shown in:  Myeclipse error prompt pageCheck that the remote server can be pinged on the local

I forgot the details. The content is roughly as follows. Two tables with the following content: SQL code + -------- + ------- + ------ + | z_code | mgr | pigs | + -------- + ------- + ------ + | 021 | zhang | 85 | 010 | wang | 70 | + -------- + -----

The unix_timestamp function for time comparison in MySql can accept a parameter or do not use a parameter. The return value is an unsigned integer. If the parameter is not used, it returns the number of seconds that have elapsed since 00:00:00,

1. Install and download the Binary Package: because mysql is 5.1.48, select the corresponding package from the official website. http://q4m.kazuhooku.com/dist/old/ Decompress the Package. copy support-files/q4m-forward to mysql installation

An error is reported when writing the following code:[Error] 1064-You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'end if 'at line 8 www.2cto.com create procedure

Two servers A: 192.168.1.1B: 192.168.1.2A (master) Serve as the master server to provide synchronization services for B (slave. Shut down the database of server A and server B at www.2cto.com, and export the database of server A to server B to

Implementation idea of auto-incrementing sequence generator l requirement u achieves the equivalent function of auto-incrementing Field Values in MySQL; the auto-incrementing Field Values in database tables in the same application cluster are

Mysql usage overview-from the basic to the stored procedure, I can see the Mysql usage summarized in the yard. I don't think it's all about me. All my stored procedures from login to advanced are involved,This part is common to me, but now I will

Analysis of Mysql and Oracle database connections Mysql 01D: \ Program Files \ MySQL Server 5.1 \ bin> mysql-u root-p02Enter password: ***** 03 Welcome to the MySQL monitor. commands end with; or \ g.04Your MySQL connection id is 183 www.2cto.com 05

Mysql SQL statements are too long and cause problems. I am doing data statistics now. MYSQL is used in the background database. There is a common requirement to query the PV of unordered users (the user's unique ID is the user's mobile phone number);

The Mysql database installation step is configure. Therefore, the installation method is Cmake, which is different from the configure version earlier than 5.5. The following are detailed installation steps: 1, extract the compressed file: tar-zxvf

Use yum in linux to install mysql 1. Check whether the installation has been installed: yum list installed mysql * rpm-qa | grep mysql * check whether there is an installation package: yum list mysql * install the mysql client: yum install mysql

Mysql distinct usage-when using mysql to filter out non-duplicate data, you sometimes need to query records with no repeated fields, although mysql provides the keyword distinct to filter out redundant duplicate records and retain only one record,

The Replication of the Replication thread Mysql is an asynchronous Replication process, from one Mysql instace (we call it the Master) to another Mysql instance (we call it the Slave ). The entire replication process between the Master and Slave is

MySQL SQL statement performance analysis set profiling = 1; select * from g_staff; show profiles www.2cto.com SHOW profile CPU, BLOCK IO FOR query 88; select * from NFORMATION_SCHEMA.PROFILING converts the results of the MySQL's show profiles

The mysql numeric processing functions floor and round are in mysql. when processing a numeric value, a numeric processing function is used. For example, if there is a float value of 2.13, you only need an integer of 2, the following functions are