By using db<>fiddle, you agree to license everything you submit by Creative Commons CC0. 3601588 fiddles created (48003 in the last week).
Declare @Main Table (sn varchar(100), amt float, sd date)
Declare @Sub Table (sn varchar(100), samt float, ssd date)
Insert Into @Main (sn, amt, sd) Values
('G', 23.00, '20170601'), ('G', 21.00, '20170602'), ('G', 33.00, '20170608')
Insert Into @Sub (sn, samt, ssd) VALUES
('G', 11.00, '20170502'), ('G', 12.00, '20170601'), ('G', -1.00, '20170601')
;WITH g1 AS
(
SELECT sn, SUM(samt) AS samt
FROM @Sub
WHERE ssd >= '20170601' AND ssd <= '20170605'
GROUP BY sn
)
, g2 AS
(
SELECT sn, SUM(amt) as amt
FROM @Main
WHERE sd >= '20170601' AND sd <= '20170605'
GROUP BY sn
)
SELECT g1.sn AS SalesPerson,
g1.samt AS SalesAmt,
(g1.samt - g2.amt) AS DiffAmp
FROM g1
JOIN g2
ON g1.sn = g2.sn;
