And this is why you should always, always, always qualify column names with the table name when you have subqueries around.
This will fail.
DELETE
FROM dbo.DimCustomer_LLF AS DCust
WHERE DCust.CustomerKey in (SELECT DISTINCT(CS.CustomerKey) FROM dbo.cdc_states AS CS);
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability