Question

I have a table with main-ids and user-ids. Each user-id has a set of their own unique main-ids, but multiple user-ids can have the same main-id. Is there anyway to increment a main-id for a specific user without having to do 2 queries?

Answer 1

If you mean like this:

User ID       Main ID
1             1
1             2
1             3
2             1
2             2
2             3

Then you’re going to need to make an INSERT trigger that finds the next MainID for that user and stores that.