[caerwy]

here's the article I learned this from. https://www.mssqltips.com/sqlservertip/2543/using-hashbytes-...

you'd add a hash column to the table you want to track. this would be used in a data warehouse where you want to track what has changed after a truncate and load. you'd keep additional tables on the side to track added/and delete hashes for a delta copy to downstream application tables.