Эти типы ситуаций обычно обрабатываются оператором слияния. Как-то так должно начаться
create table #retaildata (retail_id int,Qty int,Trigger_Suppress nvarchar(max),Next_Ship_Date datetime,Next_Ship_Qty datetime,Last_Ship_Date datetime,Last_Ship_Qty datetime,Carrier_Text datetime,
Ship_Number int,Work_Pack_Code nvarchar(max),Supplier_Part_Number int,Supplier_Inv_Qty int, Ship_Comments nvarchar(max),Last_Updt_User nvarchar(max),Last_Updt_Date datetime);
create table #massupdate (retail_id int,Qty int);
insert #retaildata (retail_id, Qty, Trigger_Suppress, Last_Updt_User) values (1, 3, 'TEST', 'Previous insert');
insert #massupdate values (1, 5), (2, 1);
select * from #retaildata;
MERGE #retaildata as target
using
(select retail_id, Qty,'N' as Trigger_suppress,null as Next_Ship_date ,null as Next_Ship_Qty,null as Last_Ship_Date ,null as Last_Ship_Qty,null as Carrier_Text,null as Ship_Number,null as Work_Pack_Code,null as Supplier_Part_Number,
null as Supplier_Inv_Qty,null as Ship_Comments,'BATCH-TRRIGER INSERT/UPDATE' as Last_Updt_User,Getdate() as Last_Updt_Date FROM #massupdate) as source
on target.retail_id=source.retail_id
when matched then update set target.Qty=source.Qty
when not matched then insert (retail_id,Qty,Trigger_Suppress,Next_Ship_Date,Next_Ship_Qty,Last_Ship_Date,Last_Ship_Qty,Carrier_Text,Ship_Number,Work_Pack_Code,Supplier_Part_Number,Supplier_Inv_Qty,
Ship_Comments,Last_Updt_User,Last_Updt_Date)
values (retail_id,Qty,Trigger_Suppress,Next_Ship_Date,Next_Ship_Qty,Last_Ship_Date,Last_Ship_Qty,Carrier_Text,Ship_Number,Work_Pack_Code,Supplier_Part_Number,Supplier_Inv_Qty,
Ship_Comments,Last_Updt_User,Last_Updt_Date);
select * from #retaildata;
drop table #massupdate, #retaildata;