Joins and Restrictions
Learn about two major database concepts: joins and restricting the output.
Understanding joins
We could spend time here with detailed explanations of every kind of join
operation: inner join
, left
and right outer join
, cross join
, full outer join
, lateral join
, and more. It just so happens that the PostgreSQL documentation covering the FROM
clause does that very well, so please read it carefully so we can instead focus on more interesting and advanced examples.
Now that we know how to easily fetch the winner of a race, it’s possible to also display all the races from a quarter with their winner:
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