I am merging the tables from 19 school databases. Everything is going very well. Yeah, it's tedious, but that is okay. I've merged the Student tables. Now, I'm merging a set of related tables, Attendance. I've carefully recorded the number of records in each Attendance table to verify my union query contains the correct count of records (208,343.) It does. Executing the query that follows to join the new random StudentID number to the union query results works excellently for most records. However, I'm missing about 680 records and can't understand where they are. I know 680 out of 208,343 is a small percentage, but lost data bugs me. I have spent a few hours attempting to understand what happened. I'll attach a screenshot of the query that results in missing data. If there is a SchoolID and a StudentID in each record, each should yield a link to the new StudentID. Yet, it's dropping some records!