SQL Server 2019

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select RequestId , FkLId , FkSId 
into TableA
from (
values
(100 , 285301 , 110 ),
(200 , 285301 , 99  ),
(300 , 285301 , 100 ),
(400 , 285301 , 98  ),
(500 , 285301 , 93  ),
(600 , 285302 , 93  ),
(700 , 285302 , 94)) v(RequestId , FkLId , FkSId )
7 rows affected

select ServiceId, FkLId, FkSId
into TableB
from (
values
(500 , 285301 , 109),
(501 , 285301 , 99 )
)v(ServiceId, FkLId, FkSId)
2 rows affected

SELECT FkSId 
FROM TableA 
WHERE FkSId NOT IN (SELECT FkSId FROM TableB where FkLId = 285301) AND FkLId = 285301 


FkSId


110

100

98

93