link issue between two tables

[Anonymous]

Hi

I have an issue with two tables, the linking  key is CustId between Table A and Table B. and I created a table chart to summarize the issue.

table A	Table B	Table B
Company	customerId	productId
X	Cus1	Prod1
-	Cus1	Prod1

the two lines have identical values in Table B and since it is the same key that relates the two table it should normally return the first  line only.

Can somebody explain this issue?

Thanks  for the help