I was trying to do that but something is not right. Unfortunately the field that I need to match on is a text field (person's name). One file is upper case and the other is lower case. So I tried to convert them to Upper case and then do the where exists. But I am doing something wrong.
Here is my script. I appreciate you taking a look.
Upper(mem_name) as Name,
FROM [lib://OPTIMA/June 2017 HRRJ_Extract_PHI_201706 (1).xlsx]