mysql assign variable in select

Variable assignment in mysql, mysql variable assignment Http://www.cnblogs.com/qixuejia/archive/2010/12/21/1913203.html   Variables in SQL server must be affirmed first and then assigned values: The local variables are identified with one @ and the

Server system Variables (System variable)The MySQL system variable (systems variables) refers to the various system variables of the MySQL instance, which are actually some system parameters that are used to initialize or set the database to occupy

Tag: color is medium tar local str local SSI GlobalDescription: Now on the market defined variables of the tutorial and books are basically stored procedures are described, but the stored procedure variables can only be used in begin...end block,

In common: case-insensitive, both variables Different points: Global variables are read-only in the system and can be modified in a configuration file Terminology classification for MySQL variables: 1. User variable: Starting with "@" in the form

Here in the CentOS6.6 system to install the MySQL source code package, to explain. 1. mysql Source package download The official download address for the MySQL installation package is: http://dev.mysql.com/downloads/mysql/5.6.html After opening

Http://www.cnblogs.com/qixuejia/archive/2010/12/21/1913203.htmlThe variables in SQL Server are first declared and then assigned:Local variables with an @ identifier, global variables with two @ (common global variables are generally defined);Declare

First, the literal value 1. StringA string is a sequence of characters that is caused by a single quotation mark ("') or double quotation mark ('" '). For example:‘a string‘"another string"If SQL Server mode is enabled for Nsi_quotes, you can refer

MySQL stored procedure SP explanation 1. Introduction to stored procedures The commonly used Operating Database Language SQL statements must be compiled and then executed before execution. the Stored Procedure (Stored Procedure) is a set of SQL

1. Introduction to stored procedures The commonly used operating database language SQL statements must be compiled and then executed before execution. The Stored Procedure (Stored Procedure) is a set of SQL statements for specific functions, after

Key_buffer_size Set this variable to assign a space of the specified size to the key buffer (or key cache). But the operating system will only be allocated when the space is actually used. For example, setting the key buffer size to 1GB does not