> What do you want to see if there's more than one sale date with the lowest price? Either one is fine. PostgreSQL has an extension (DISTINCT ON) that allows

> What do you want to see if there's more than one sale date with the lowest price? Either one is fine. PostgreSQL has an extension (DISTINCT ON) that allows to do what I want without subqueries. But standard SQL is simply deficient in this regard, it should be straightforward but it's not.