Db2 11.1

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WITH 
  IL (BU, WC, Order#, Doc_Type, Trans_Date, Qty) AS
(
VALUES
  ('BU-1', 'WC-1', 1, 'IC', '8/7/20', 20)
, ('BU-1', 'WC-1', 1, 'IC', '8/7/20', 40)
, ('BU-1', 'WC-1', 2, 'IC', '8/7/20', 10)
, ('BU-1', 'WC-2', 3, 'IC', '8/7/20', 40)
, ('BU-1', 'WC-2', 3, 'IC', '8/7/20', 10)
, ('BU-2', 'WC-4', 6, 'IC', '8/7/20', 10)
, ('BU-2', 'WC-5', 5, 'IC', '8/7/20', 60)
, ('BU-1', 'WC-1', 2, 'IC', '8/6/20', 50)
, ('BU-1', 'WC-3', 4, 'IC', '8/6/20', 30)
, ('BU-2', 'WC-5', 5, 'IC', '8/5/20', 50)
, ('BU-2', 'WC-5', 7, 'IC', '8/1/20', 20)
, ('BU-2', 'WC-5', 8, 'IC', '7/26/20',30)
, ('BU-2', 'WC-5', 8, 'IC', '7/25/20',50)
)
, WO (BU, WC, Order#, Hours_Type, GL_Date, Hours) AS
(
VALUES
  ('BU-2', 'WC-4', 6, 3, '8/8/20', 7.4  )
, ('BU-1', 'WC-1', 1, 3, '8/7/20', 3.92 )
, ('BU-1', 'WC-2', 3, 3, '8/7/20', 8    )
, ('BU-1', 'WC-2', 3, 3, '8/7/20', 7    )
, ('BU-1', 'WC-3', 4, 3, '8/7/20', 6.2  )
, ('BU-2', 'WC-4', 6, 3, '8/7/20', 1.1  )
, ('BU-1', 'WC-1', 2, 3, '8/6/20', 1.57 )
, ('BU-2', 'WC-5', 7, 3, '8/1/20', 3.9  )
, ('BU-2', 'WC-5', 8, 3, '7/25/20', 11.3)
)

SELECT
  COALESCE(ILG.WEEK, WOG.WEEK) AS WEEK
, COALESCE(ILG.BU, WOG.BU) AS BU
, COALESCE(ILG.WC, WOG.WC) AS WC
, COALESCE(WOG.Hours, 0) AS HOURS
, COALESCE(ILG.Qty, 0) AS QTY
FROM
(
SELECT BU, WC, WEEK(TO_DATE(GL_Date, 'MM/DD/YY')) AS Week, SUM(Hours) AS Hours
FROM WO
GROUP BY BU, WC, WEEK(TO_DATE(GL_Date, 'MM/DD/YY'))
) WOG
FULL JOIN
(
SELECT 
  BU, WC
, WEEK(TO_DATE(Trans_Date, 'MM/DD/YY')) AS Week
, SUM(Qty) AS Qty
FROM IL
GROUP BY BU, WC, WEEK(TO_DATE(Trans_Date, 'MM/DD/YY'))
) ILG ON ILG.BU = WOG.BU AND ILG.WC = WOG.WC AND ILG.WEEK = WOG.WEEK
ORDER BY 1 DESC, 2, 3;

WEEK	BU	WC	HOURS	QTY
32	BU-1	WC-1	5.49	120
32	BU-1	WC-2	15.00	50
32	BU-1	WC-3	6.20	30
32	BU-2	WC-4	8.50	10
32	BU-2	WC-5	0.00	110
31	BU-2	WC-5	3.90	50
30	BU-2	WC-5	11.30	50