Global variables have values set by the database server. For example, the global variable @@version has a value that is the current version number of the database server.

Global variables are distinguished from local and connection-level variables by having two @ signs preceding their names. For example, @@error and @@rowcount are global variables. Users cannot create global variables, and cannot update the values of global variables directly.

Some global variables, such as @@identity, hold connection-specific information, and so have connection-specific values. Other variables, such as @@connections, have values that are common to all connections.

Global variable and special constants

The special constants (for example, CURRENT DATE, CURRENT TIME, USER, and SQLSTATE) are similar to global variables.

The following statement retrieves a value of the version global variable.

SELECT @@version;

In procedures and triggers, global variables can be selected into a variable list. The following procedure returns the server version number in the ver parameter.

CREATE PROCEDURE VersionProc ( OUT ver VARCHAR(100) )
 BEGIN
   SELECT @@version
   INTO ver;
 END;

In Embedded SQL, global variables can be selected into a host variable list.

List of global variables

The following table lists the global variables available in SQL Anywhere. Some global variables are supplied for compatibility with Transact-SQL, and return a fixed value of either 0, 1, or NULL, as noted.