Assign and combine operation in unique id

Hi all,

   Performed cleansing and matching for Table-1 and generated unique id using assign operation.

   Next day Table-2 is passed, matched records in Table-1 and Table-2 will get same unique id and unique records will get new unique id.

   Is assign combine operation will suit this requirement???

   If it suits, how to pass Table-2 to match records from Table-1 any transforms I have to use to compare Table-1 and Table-2.

Thank you.