I was thinking a basic SELECT X FROM Y WHERE Z Sql query that can be learned in a day by someone familiar with programming. I don’t know enough to know what qualifies as advanced.
I comment I read somewhere was that SQL goes from basic to advanced with nothing in between. It's a slippery slope of course: you start writing your own query and then you figure a more sophisticated query would be helpful and pretty soon you're having to care about optimisation and indexes.