Try this:
DECLARE @Fee_Assign_to_Students TABLE(cls_SecId INT, S_Adm_No INT, FHeadId INT, Apr INT, May INT, Jun INT, Jul INT, Aug INT, Sep INT, Oct INT, Nov INT, Dec INT, Jan INT, Feb INT, Mar INT)
INSERT INTO @Fee_Assign_to_Students (cls_SecId, S_Adm_No, FHeadId, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec, Jan, Feb, Mar)
VALUES(1, 1001, 4, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100),
(1, 1001, 5, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100),
(1, 1001, 5, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100)
SELECT cls_SecId, S_Adm_No, Installment, SUM(Amount) AS AMount, CASE
WHEN Installment = 'Q1' THEN '15.04.2015'
WHEN Installment = 'Q2' THEN '15.07.2015'
WHEN Installment = 'Q3' THEN '15.10.2015'
WHEN Installment = 'Q4' THEN '15.01.2015' END AS Payable_Date
FROM (
SELECT cls_SecId, S_Adm_No, Apr + May + Jun AS Q1, Jul + Aug + Sep AS Q2, Oct + Nov + Dec AS Q3, Jan + Feb + Mar AS Q4
FROM @Fee_Assign_to_Students
) AS Pvt
UNPIVOT (Amount FOR Installment IN (Q1, Q2, Q3, Q4)) AS unPvt
GROUP BY cls_SecId, S_Adm_No, Installment
Result:
cls_SecId S_Adm_No Installment Amount Payable_Date
1 1001 Q1 900 15.04.2015
1 1001 Q2 900 15.07.2015
1 1001 Q3 900 15.10.2015
1 1001 Q4 900 15.01.2015
For further details, please see:
Using PIVOT and UNPIVOT[
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CASE (Transact-SQL)[
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