CALL statement

Description

Invokes a procedure.

Syntax

Syntax 1

variable = ] CALL procedure-name ( [ expression ] [ , … ] )

Syntax 2

variable = ] CALL procedure-name ( [ parameter-name = expression ] [ , … ] )

Examples

Example 1

This example calls the sp_customer_list procedure. This procedure has no parameters, and returns a result set:

CALL sp_customer_list()

Example 2

This DBISQL example creates a procedure to return the number of orders placed by the customer whose ID is supplied, creates a variable to hold the result, calls the procedure, and displays the result:

CREATE PROCEDURE OrderCount (IN CustomerID INT, OUT Orders INT)
BEGIN
SELECT COUNT("DBA".SalesOrders.ID)
INTO Orders
FROM "DBA".Customers
KEY LEFT OUTER JOIN "DBA".SalesOrders
WHERE "DBA".Customers.ID = CustomerID ;
END
go
-- Create a variable to hold the result
CREATE VARIABLE Orders INT
go

-- Call the procedure, FOR customer 101
-- -----------------------------
CALL OrderCount ( 101, Orders) 
go
--------------------------------
--  Display the result
SELECT Orders FROM DUMMY 
go

Usage

CALL invokes a procedure that has been previously created with a CREATE PROCEDURE statement. When the procedure completes, any INOUT or OUT parameter values are copied back.

You can specify the argument list by position or by using keyword format. By position, arguments match up with the corresponding parameter in the parameter list for the procedure. By keyword, arguments match the named parameters.

Procedure arguments can be assigned default values in the CREATE PROCEDURE statement, and missing parameters are assigned the default value, or, if no default is set, NULL.

Inside a procedure, CALL can be used in a DECLARE statement when the procedure returns result sets. See Chapter 1, “Using Procedures and Batches” in the System Administration Guide: Volume 2.

Procedures can return an integer value (as a status indicator, say) using the RETURN statement. You can save this return value in a variable using the equality sign as an assignment operator:

CREATE VARIABLE returnval INT ;
returnval = CALL proc_integer ( arg1 = val1, ... )

Side effects

None.

Standards

Permissions

Must be the owner of the procedure, have EXECUTE permission for the procedure, or have DBA authority.

See also

CREATE PROCEDURE statement

GRANT statement