Postgres implicitly shaped temporary tables. Syntactic sugar I am not aware of?

问题

I'm writing a batch mode update function and at the moment it looks like this :

CREATE OR REPLACE FUNCTION gen_category_counts()
RETURNS VOID as $$
BEGIN
    CREATE TEMPORARY TABLE category_stats ON COMMIT DROP AS
    WITH
        PC as(
            SELECT category_id, COUNT(*)
            FROM forum_posts fp
            INNER JOIN forum_topics ft
            ON ft.forum_id = fp.forum_id
            AND ft.id = fp.topic_id
            GROUP BY category_id
       ), 
        tc as(
            SELECT category_id, COUNT(*)
            FROM forum_topics
            GROUP BY category_id 
        )
    SELECT tc.category_id,tc.count AS topic_count, pc.count AS post_count
    FROM tc,pc
    WHERE tc.category_id = pc.category_id;

    UPDATE forum_category_nodes fcn 
    set post_count = category_stats.post_count, topic_count = category_stats.topic_count
    from category_stats
    where fcn.id = category_stats.category_id; 
END;
$$ LANGUAGE plpgsql;

Is there some syntactic sugar that is better than having to write out a whole sentence to declare a temp table that lives only for the duration of the function ?

Sql Server has a select into #tablename (can't remember the exact syntax, it could be @tablename). I have seen this style of syntax used on the mailing lists, but it's syntactically incorrect, also the EBBF select into documentation mentions temporary tables as well right next to the into clause.

So if postgres does have better sugar for implicitly defined scoped temporary tables, what is it ? :D

p.s., I'm going to be writing procedures with hundreds of lines of logic and these things add up :D

回答1:

OK, one minor shortcut:

CREATE TEMP TABLE category_stats ON COMMIT DROP AS

Other than that, for all I know, you are using the simplest form in your question - and I have been using temporary tables a lot over the last couple of years.

Honestly, I don't see why a few descriptive key words should bother me.

来源：https://stackoverflow.com/questions/11551627/postgres-implicitly-shaped-temporary-tables-syntactic-sugar-i-am-not-aware-of

标签

postgresql

stored-procedures

syntactic-sugar