Dynamically Filter One Table with Output of Another Prior to Joining

[ACharChar]

In my workflow, I'm needing to join a number of tables. These tables though are remarkably large > 50 GB. My workflow is not efficient when I allow both tables to fully load then join on a common field. In table A, I have parameters that limit the size of the table and would then like to join the output with table B. This would typically happen in the WHERE clause of the SQL. This clause limiting having to fully load Table B. How can I leverage the output of Table A to pass into Table B? Table A will produce a list of values that I could potentially pass into Table B, then join the two tables. 

[wwatson]

@ACharChar  Are the tables actually files rather than database tables?

[CharlieS · Accepted solution]

I would suggest performing the join inside the database so the tables don't have to be completely loaded and just the joined records you're looking for is output. As long as the table fields are properly indexed, this should not be a problem. You can perform this join within the query of an Input tool, or use In-Database tools to build this process. 

If you can share the names of the fields and tables, I'm sure the Community can help with this.