Connection-level variables are declared with the CREATE VARIABLE statement. Connection-level variables can be passed as parameters to procedures.

The syntax for the CREATE VARIABLE statement is as follows:

CREATE VARIABLE variable-name data-type

When a variable is created, it is initially set to NULL. The value of connection-level variables can be set in the same way as local variables, using the SET statement or using a SELECT statement with an INTO clause.

Connection-level variables exist until the connection is terminated, or until the variable is explicitly dropped using the DROP VARIABLE statement. The following statement drops the variable con_var:

DROP VARIABLE con_var;

 Example

CREATE VARIABLE con_var INT;
SET con_var = 10;
MESSAGE 'con_var = ', con_var TO CLIENT;

 Standards and compatibility