Guru: A More Efficient Way To Merge With SQL

October 15, 2018 Mike Larsen

Lately, I’ve been using the merge statement in my programs to insert or update rows in a table. I recently came across a situation where a program using merge was running every few minutes and performing updates to thousands of rows each time it ran. Since this table was journaled, it was obvious some re-design was necessary.

For those unfamiliar with the merge statement, it is sometimes referred to as an “upsert.” That means it will either perform an update or an insert. In RPG terms, I like to compare it to a chain operation. With a chain, you check …