Hi,
The Examples section in the documentation for the SELECT command [1]
only contains a single example on how to join two tables,
which is written in SQL-89 style:
SELECT f.title, f.did, d.name, f.date_prod, f.kind
FROM distributors d, films f
WHERE f.did = d.did
I think it's good to keep this example query as it is,
and suggest we add the following equivalent queries:
SELECT f.title, f.did, d.name, f.date_prod, f.kind
FROM distributors d
JOIN films f ON f.did = d.did
SELECT f.title, f.did, d.name, f.date_prod, f.kind
FROM distributors d
JOIN films f USING (did)
SELECT f.title, f.did, d.name, f.date_prod, f.kind
FROM distributors d
NATURAL JOIN films f
I also think it would be an improvement to break up the from_item below into
three separate items,
since the optional NATURAL cannot occur in combination with ON nor USING.
from_item [ NATURAL ] join_type from_item [ ON join_condition | USING (
join_column [, ...] ) [ AS join_using_alias ] ]
Suggestion:
from_item join_type from_item ON join_condition
from_item join_type from_item USING ( join_column [, ...] ) [ AS
join_using_alias ]
from_item NATURAL join_type from_item
This would be more readable imo.
I picked the order ON, USING, NATURAL to match the order they are described in
the FROM Clause section.
/Joel
[1] https://www.postgresql.org/docs/current/sql-select.html
