update t1
set [Cust PO No] = t2.[Customer PO_ No_]
From dbo.[TransNet Corporation_Test$Sales Commission] t1
join dbo.[TransNet Corporation_Test$Sales Invoice Header] t2
on t2.[No_] = t1.[Inv No]
AND t2.[Posting Date] = t1.[Posting Date]
Harsh Athalye
India.
"The IMPOSSIBLE is often UNTRIED"