I'm afraid I'm not privileged to that info.
Customer ID has differing values, all similar to A123 or C883 (etc..). CreditCheckLevel either has the matching CustomerID for that row - hence the lookup between the two values, or a completely different value in which it will have a NULL when used in the LEFT JOIN.
The odd thing is, the actual CustomerID value used in the returned dataset (dimension) is from the same table which is the left sided table of the LEFT JOIN.
I'm just wondering what this query does exactly, and is a LEFT JOIN needed? I imagine you gurus could decipher it and answer my question. Thanks.