2 ms·
Don't have a suitable database to test on but I'm pretty sure standard SQL allows you to join on a subselect that limits its result to one.
by cess11 2y ago
Don't have a suitable database to test on but I'm pretty sure standard SQL allows you to join on a subselect that limits its result to one.
- singron 2y agoYou probably want to use LATERAL JOIN, which will compute the subquery for each left hand row. Otherwise it's computed just once.
- cess11 2y agoWith SQL there are commonly several options available, and tradeoffs might not be obvious until it's tested against a real data set. Sometimes even an EXPLAIN that looks good still has some drawback in production, though in my experience it's very rare. I like that though, I have a preference for REPL style development and fleshing things out interactively. Enough so that I build Java like that, hacking things out directly in tests.