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Tuesday, October 14, 2014
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Calling a Procedure from another Procedure: SQL

7:58 PMTuesday, October 14, 2014
At times, you might need to use the values returned by a procedure in another procedure. For this, you can execute or call one procedure from within another procedure.

A procedure that calls or executes another procedure is known as the calling procedure, and the procedure that is called or executed by the calling procedure is termed as the called procedure. You can also execute a procedure from another procedure if you need to use the functionality provide by one into another.

Consider the previous example where the prcGetEmployeeDetail procedure returns the employee details for a given employee ID. You can create the prcDisplayEmployeeStatus procedure, which accepts the employee ID of an employee as input and displays the department name and shift ID where the employee is working along with the manager ID and the title employee. To perform this task, you need to call the prcGetEmployeeDetail procedure from the prcDisplayEmployeeStatus procedure, as shown in the following statement:

CREATE PROCEDURE prcDisplayEmployeeStatus @EmpId int
AS
BEGIN
DECLARE @DepName char (50)
DECLARE @ShiftId int
DECLARE @ReturnValue int
EXEC @ReturnValue = prcGetEmployeeDetail @EmpId,
@ DepName OUTPUT,
@ ShiftId OUTPUT
IF (@ReturnValue = 0)
BEGIN
PRINT ‘The details of an employee with ID: ‘ + convert (char (10), @EmpId)
PRINT ‘shift ID: ‘ + convert ( char (1), @shiftId)
SELECT ManagerID, Title FROM HumanResources.Employee
WHERE EmployeeID = @EmpID
END
ELSE
PRINT ‘No records found for the given employee’
END

To execute the preceding code, you need to execute the following statement:
EXEC prcDisplayEmployeeStatus 2

SQL Server provides a function, @@ROWCOUNT, which return the number of rows affected by the last statement. You can use this statement in the IF construct to check the result of the last statement that executed.

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