Stored Procedure with Optional DateTime Parameters in SQL Server

Question

How to write this select query in SQL Server when the datetime parameters (@StartDate & @EndDate) are optional in this stored procedure?

CREATE PROCEDURE [dbo].[prSearchEmployees]
(
    @Id INT = NULL
    ,@FullName VARCHAR(20) = NULL
    ,@Age INT = NULL
    ,@StartDate = NULL
    ,@EndDate = NULL
)
AS
BEGIN
   SELECT * 
   FROM Employee 
   WHERE Id = ISNULL(@Id, Id) 
     AND FullName LIKE ISNULL(@FullName + '%', FullName)
     AND Age = ISNULL(@Age, Age)
END

Answer 1

I know this is an old post but there are alternatives that are a bit more concise. This post outlines it perfectly. So in the previous example you would do something like

 CREATE PROCEDURE [dbo].[prSearchEmployees]
(
 @Id INT = NULL
,@FullName VARCHAR(20) = NULL
,@Age INT = NULL
,@StartDate DATETIME = NULL
,@EndDate DATETIME = NULL
)
AS
BEGIN    

SELECT * FROM Employee 
     WHERE ((@Id IS NULL) OR (Id = @Id))
       AND ((@FullName IS NULL) OR (FullName LIKE @FullName + '%'))
       AND ((@Age IS NULL) OR (Age = @Age))
       AND ((@SDate IS NULL) OR (Date BETWEEN @SDate AND @EDate))

Answer 2

You could add two new variables at the top of your sproc.. And assign based on the ISNULL function

CREATE PROCEDURE [dbo].[prSearchEmployees]
(
 @Id INT = NULL
,@FullName VARCHAR(20) = NULL
,@Age INT = NULL
,@StartDate DATETIME = NULL
,@EndDate DATETIME = NULL
)
AS
BEGIN

DECLARE @SDate DATETIME
DECLARE @EDate DATETIME

SET @SDate = ISNULL(@StartDate, GETDATE())
SET @EDate = ISNULL(@EndDate, GETDATE())


SELECT * FROM Employee 
     WHERE Id = ISNULL(@Id, Id) 
       AND FullName LIKE ISNULL(@FullName + '%', FullName)
       AND Age = ISNULL(@Age, Age)
       AND Date BETWEEN @SDate AND @EDate