MULTIPLE Cases in Select Query in SQL Server

Question

I have a Scenario in my SQL query is that I have to find out babies records with given dates but from multiple years Suppose My Selection Date is = 01/Jan/2014 to 31/Jan/2014

I have another parameter that is year, that it asks me randomly to select data of babies born of previous (1~3 Years) Suppose If my current Selected dates are of Years 2014 and my year variable has value 2 then

I must bring data of babies respectively to the current year and also a year less then of current date and so on Below is my Given Scenario

--------------------------------------------
--  BABIES_TABLE
ID |    Name         |  Age |   DOB         |
--------------------------------------------
1           JKL         3       21/Jan/2012
2           DEF         2       09/Jan/2013
3           ABC         1       04/Jan/2014
4           XYZ         1       02/Feb/2014

-- Date Range [01/Jan/2014 - 31/Jan/2014]
-- Year = 2
---------------------------------------------
ID     |    Name    |   Age |   DOB         |
---------------------------------------------
3           ABC         1       04/Jan/2014
2           DEF         2       09/Jan/2013



-- Date Range [01/Jan/2014 - 31/Jan/2014]
-- Year = 3
---------------------------------------------
ID     |    Name    |   Age |   DOB         |
---------------------------------------------
3           ABC         1       04/Jan/2014
2           DEF         2       09/Jan/2013
1           JKL         3       21/Jan/2012

below is my SQl Query which is ambiguous and having error.I have try with single date comparison , Its fine But when i add OR condition, it gives me error

--MY SQL Query is Below

DECLARE @startDate AS DATETIME
DECLARE @enddate AS DATETIME
DECLARE @y AS INT
SET @startDate='2012-10-12'
SET @enddate='2012-10-20'
SET @y=2

SELECT * FROM BABIES_TABLE
WHERE 
        CAST(CONVERT(VARCHAR, BABIES_TABLE.DOB, 111) AS DATETIME) >= CASE            
            --If entered Year = 1
            WHEN @y = 1 THEN        
            (@startDate)                                     
            --If entered Year = 2
            WHEN @y = 2 THEN
                  CASE
                  (@startDate)
                  END                  
            OR
                  CASE
                  YEAR(@startDate-1)
                  END            

            WHEN @y = 3 THEN
                  CASE
                  (@startDate)
                  END          
            OR
                  CASE
                  YEAR(@startDate-1)
                  END
            OR
                  CASE
                  YEAR(@startDate-2)
                  END
        END
    END
  AND
        CAST(CONVERT(VARCHAR, BABIES_TABLE.DOB, 111) AS DATETIME) <= CASE
            WHEN @y = 1 THEN        
            (@enddate)                                     

            WHEN @y = 2 THEN
                  CASE
                  (@enddate)
                  END                  
            OR
                  CASE
                  YEAR(@enddate-1)
                  END            

            WHEN @y = 3 THEN
                CASE
                (@enddate)
                END          
            OR
                CASE
                YEAR(@enddate-1)
                END
            OR
                CASE
                YEAR(@enddate-2)
                END
        END
    END

Answer 1

Here is what I have achieved my desired result, but I guess it could be possible using Case in Where.

---------------------------------------------

ID |    Name         |  Age |   DOB         |
--------------------------------------------

1   Abid                 6  2008-01-01
2   Zahid                6  2008-01-10
3   Laila                5  2009-01-15
4   Ali                  5  2010-01-26
5   Kali                 4  2011-01-19
6   Sali                 3  2012-01-08
7   Brone                2  2013-01-11
8   Dilche               2  2013-01-29
9   Alpechino            3  2012-08-20

Here is my stored procedure.

--MY SQL Query is Below
CREATE PROCEDURE BabyUnionData
@Year AS INT,
@Start_Date as varchar(30),
@End_Date as Varchar(30)
AS
BEGIN


DECLARE @startDate AS DATETIME
DECLARE @enddate AS DATETIME
DECLARE @y AS INT
SET @startDate=@Start_Date
SET @enddate=@End_Date
--SELECt * FROM BABIES_TABLE
PRINT 'For One Year'
SET @y=@Year

IF @y = 1       
    BEGIN
    PRINT 'For One Year'
        SELECT * FROM BABIES_TABLE
        WHERE 
            CAST(CONVERT(VARCHAR, BABIES_TABLE.DOB, 111) AS DATETIME) >= @startDate
            AND
            CAST(CONVERT(VARCHAR, BABIES_TABLE.DOB, 111) AS DATETIME) <= @enddate
    END
ELSE IF @y = 2  
    BEGIN
    PRINT 'For Two Years'
        SELECT * FROM BABIES_TABLE
        WHERE 
            CAST(CONVERT(VARCHAR, BABIES_TABLE.DOB, 111) AS DATETIME) >= @startDate
            AND
            CAST(CONVERT(VARCHAR, BABIES_TABLE.DOB, 111) AS DATETIME) <= @enddate
        UNION
        SELECT * FROM BABIES_TABLE
        WHERE 
            CAST(CONVERT(VARCHAR, BABIES_TABLE.DOB, 111) AS DATETIME) >= DATEADD(Year,-1,@startDate)
            AND
            CAST(CONVERT(VARCHAR, BABIES_TABLE.DOB, 111) AS DATETIME) <= DATEADD(Year,-1,@enddate)
    END
    ELSE IF @y = 3
    BEGIN
        PRINT 'For Three Years'
        SELECT * FROM BABIES_TABLE
        WHERE 
            CAST(CONVERT(VARCHAR, BABIES_TABLE.DOB, 111) AS DATETIME) >= @startDate
            AND
            CAST(CONVERT(VARCHAR, BABIES_TABLE.DOB, 111) AS DATETIME) <= @enddate
        UNION
        SELECT * FROM BABIES_TABLE
        WHERE 
            CAST(CONVERT(VARCHAR, BABIES_TABLE.DOB, 111) AS DATETIME) >= DATEADD(Year,-1,@startDate)
            AND
            CAST(CONVERT(VARCHAR, BABIES_TABLE.DOB, 111) AS DATETIME) <= DATEADD(Year,-1,@enddate)
        UNION
        SELECT * FROM BABIES_TABLE
        WHERE 
            CAST(CONVERT(VARCHAR, BABIES_TABLE.DOB, 111) AS DATETIME) >= DATEADD(Year,-2,@startDate)
            AND
            CAST(CONVERT(VARCHAR, BABIES_TABLE.DOB, 111) AS DATETIME) <= DATEADD(Year,-2,@enddate)
    END
    ELSE IF @y = 4
    BEGIN
    PRINT 'For Four Years'
        SELECT * FROM BABIES_TABLE
        WHERE 
            CAST(CONVERT(VARCHAR, BABIES_TABLE.DOB, 111) AS DATETIME) >= @startDate
            AND
            CAST(CONVERT(VARCHAR, BABIES_TABLE.DOB, 111) AS DATETIME) <= @enddate
        UNION
        SELECT * FROM BABIES_TABLE
        WHERE 
            CAST(CONVERT(VARCHAR, BABIES_TABLE.DOB, 111) AS DATETIME) >= DATEADD(Year,-1,@startDate)
            AND
            CAST(CONVERT(VARCHAR, BABIES_TABLE.DOB, 111) AS DATETIME) <= DATEADD(Year,-1,@enddate)
        UNION
        SELECT * FROM BABIES_TABLE
        WHERE 
            CAST(CONVERT(VARCHAR, BABIES_TABLE.DOB, 111) AS DATETIME) >= DATEADD(Year,-2,@startDate)
            AND
            CAST(CONVERT(VARCHAR, BABIES_TABLE.DOB, 111) AS DATETIME) <= DATEADD(Year,-2,@enddate)
        UNION
        SELECT * FROM BABIES_TABLE
        WHERE 
            CAST(CONVERT(VARCHAR, BABIES_TABLE.DOB, 111) AS DATETIME) >= DATEADD(Year,-3,@startDate)
            AND
            CAST(CONVERT(VARCHAR, BABIES_TABLE.DOB, 111) AS DATETIME) <= DATEADD(Year,-3,@enddate)
    END
    ELSE IF @y = 5
    BEGIN
    PRINT 'For Five Years'
        SELECT * FROM BABIES_TABLE
        WHERE 
            CAST(CONVERT(VARCHAR, BABIES_TABLE.DOB, 111) AS DATETIME) >= @startDate
            AND
            CAST(CONVERT(VARCHAR, BABIES_TABLE.DOB, 111) AS DATETIME) <= @enddate
        UNION
        SELECT * FROM BABIES_TABLE
        WHERE 
            CAST(CONVERT(VARCHAR, BABIES_TABLE.DOB, 111) AS DATETIME) >= DATEADD(Year,-1,@startDate)
            AND
            CAST(CONVERT(VARCHAR, BABIES_TABLE.DOB, 111) AS DATETIME) <= DATEADD(Year,-1,@enddate)
        UNION
        SELECT * FROM BABIES_TABLE
        WHERE 
            CAST(CONVERT(VARCHAR, BABIES_TABLE.DOB, 111) AS DATETIME) >= DATEADD(Year,-2,@startDate)
            AND
            CAST(CONVERT(VARCHAR, BABIES_TABLE.DOB, 111) AS DATETIME) <= DATEADD(Year,-2,@enddate)
        UNION
        SELECT * FROM BABIES_TABLE
        WHERE 
            CAST(CONVERT(VARCHAR, BABIES_TABLE.DOB, 111) AS DATETIME) >= DATEADD(Year,-3,@startDate)
            AND
            CAST(CONVERT(VARCHAR, BABIES_TABLE.DOB, 111) AS DATETIME) <= DATEADD(Year,-3,@enddate)
        UNION
        SELECT * FROM BABIES_TABLE
        WHERE 
            CAST(CONVERT(VARCHAR, BABIES_TABLE.DOB, 111) AS DATETIME) >= DATEADD(Year,-4,@startDate)
            AND
            CAST(CONVERT(VARCHAR, BABIES_TABLE.DOB, 111) AS DATETIME) <= DATEADD(Year,-4,@enddate)
    END
END

--Here is Use of StoredProcedure

Exec BabyUnionData 5,'01-01-2014','01-31-2014'