Compare two lists, but remove duplicates before join

[RCern]

Quick question.  I am combining two sources of data, Source A and Source B.  How can I compare the two sources and see if a Customer ID exists in both and if so, leave the one in Source B out when combining so that there are not two records for the Customer?

[binuacs]

@RCern @Use the join tool and join with the customer id as key, deselect the right customer id field from the join tool configuration, the J-anchor will have the output which matching customer id records from both sources

[RCern]

@binuacs But then how do I exclude those specific matched Customer IDs from the combined list of both sets?

[binuacs]

@RCern @Can you explain your use case with an example for better understanding 

[abe_ibanez]

Hello, 
If you use a Join tool, it will not combine the data from both sources in the J output anchor; just the ones you select within the Join tool. 

Here is an example: 

Source A (Top):

Join Tool configuration:

Output after Union tool:

I hope this helps.