[ttfkam]

I love LATERALs, but this still fits within set theory and a bulk application rather than an iterative for-loop. It may even be implemented as a for-loop within the engine, but SQL being declarative abstracts that away from the query interface.

It's sets all the way down. A set of f(x) is still a set.

[gavinray]

Lets get even more cursed then:

    CREATE TEMP TABLE temp_results(value int, value_squared int);

    DO $$
    DECLARE
        r int;
    BEGIN
        FOR r IN SELECT generate_series FROM generate_series(1,5)
        LOOP
            INSERT INTO temp_results VALUES (r, r * r);
        END LOOP;
    END$$;

    SELECT * FROM temp_results;

[fifilura]

Uw you win, I guess. Already started to think what I would write in that code review comment ;)

[koolba]

At the very least mention that re-running the SELECT in the same connection would include the prior results as well because they are preserved across commands within the same connection.

[ttfkam]

Ha! plpgsql's seemingly sole purpose is to inject imperative code into a set-based environment. Probably does it more smoothly than most pl languages, but that's at the cost of imperative clarity.

But you're right. Postgres does allow for-loops like this. (They're also slower than the equivalent set-oriented approach.)