Flexible searching on tables

CREATE PROCEDURE get_rows

@date_received      datetime, -- always supplied
@area_code varchar(50) = NULL, -- can be empty
@source_of_budget varchar(20) = NULL -- can be empty

AS

--//
DECLARE @result TABLE
(
int_row_id integer,
area_code varchar(50),
date_received datetime,
budget_source varchar(20)
)

--//
--//
INSERT
@result
(
int_row_id,
area_code,
date_received,
budget_source
)
--//
SELECT 
int_row_id, -- identity column
area_code,
date_received,
        budget_source
FROM 
dbo.source_table
WHERE 
( CONVERT(CHAR(10),date_received,101) > CONVERT(CHAR(10),@date_received,101) )

--//
IF @area_code IS NOT NULL
BEGIN
--//
DELETE

FROM 
@result

FROM
@resultt1

LEFT JOIN 
(
SELECT 
int_row_id
FROM 
@result
WHERE ( area_code = @area_code )
) t2

ON t1.int_row_id = t2.int_row_id

WHERE
t2.int_row_id IS NULL
--//
END

--//
IF @source_of_budget IS NOT NULL
BEGIN
--//
IF @source_of_budget = 'Asia'
BEGIN
--//

DELETE

FROM 
@result

FROM
@resultt1

LEFT JOIN 
(
SELECT 
int_row_id
FROM 
@result
WHERE ( budget_source IN ('Philippines','Korea','Japan' ) )
) t2

ON t1.int_row_id = t2.int_row_id

WHERE
t2.int_row_id IS NULL

--//
END

--//
--//
ELSE
--//
--//

BEGIN
--//

DELETE

FROM 
@result

FROM
@resultt1

LEFT JOIN 
(
SELECT 
int_row_id
FROM 
@result
WHERE ( budget_source = @source_of_budget )
) t2

ON t1.int_row_id = t2.int_row_id

WHERE
t2.int_row_id IS NULL

--//
END

END

--//
--//
-- final select
--//
--//
SELECT
* -- whatever you want
--//
FROM
dbo.source_table source
--//
INNER JOIN (SELECT DISTINCT int_row_id FROM @result) result
ON source.int_row_id = result.int_row_id
--//
ORDER BY
--//
source.int_row_id


RETURN