set-valued function called in context that cannot accept a set

Question

I am receiving the error:

set-valued function called in context that cannot accept a set

when executing this function at RETURN QUERY EXECUTE line:

PLSQL $ cat lookup_email.pl 
CREATE OR REPLACE FUNCTION app.lookup_email(ident_id bigint,sess bigint,company_id bigint,email varchar)
RETURNS SETOF RECORD as $$
DECLARE
    rec RECORD;
    comp_id bigint;
    server_session bigint;
    schema_name varchar;
    query varchar;
BEGIN
    schema_name:='comp' || company_id;
    select app.session.session into server_session from app.session where app.session.identity_id=ident_id and app.session.session=sess;
    IF FOUND
    THEN
        BEGIN
            query:='SELECT i.email,u.user_id FROM app.identity as i,' || schema_name || '.uzer as u WHERE i.email like ''%' || email || '%'' and i.identity_id=u.identity_id';
            RAISE NOTICE 'executing: %',query;
            RETURN QUERY EXECUTE query;
            RETURN;
        EXCEPTION
            WHEN OTHERS THEN
                RAISE NOTICE ' query error (%)',SQLERRM;

        END;
    END IF;
END;
$$ LANGUAGE plpgsql;

This is the ouput from psql:

dev=> select app.lookup_email(4,730035455897450,6,'u');
NOTICE:  executing: SELECT i.email,u.user_id FROM app.identity as i,comp6.uzer as u WHERE i.email like '%u%' and i.identity_id=u.identity_id
NOTICE:   query error (set-valued function called in context that cannot accept a set)
 lookup_email 
--------------
(0 rows)

I know the query doesn't contain any error, because it works in another psql session:

dev=> SELECT i.email,u.user_id FROM app.identity as i,comp6.uzer as u WHERE i.email like '%u%' and i.identity_id=u.identity_id;
     email      | user_id 
----------------+---------
 [email protected] |       1
(1 row)

So why is Postgres complaining if I declared my function being as RETURNS SETOF RECORD? Where is my error?

Solution

So, why is Postgres complaining if I declared my function being a SET of RECORD ??? Where is my error?

1. Call your Set Returning Function in a FROM clause.
2. Always specify your types.

It's called a Set Returning Function, but you want to specify the composite type

This is totally valid,

RETURNS SETOF RECORD $$

However, you may have to call it with,

SELECT email, user_id
FROM 
    app.lookup_email(4,730035455897450,6,'u')
    AS t(email text, user_id integer)

The context which you can not call an untyped SRF in, is one which does not have a table-definition. This syntax can get nasty, so just it's easier to change RETURNS SETOF RECORD to

RETURNS TABLE(email text, user_id integer) AS $$

and use the function without the column definition list

SELECT email, user_id
FROM app.lookup_email(4,730035455897450,6,'u')

Find more information in the docs

Comments

[Erwin Brandstetter]

What Evan explains is all true and good, but you still shouldn't get this error with current Postgres. What's your version? (SELECT version())

[Luan Huynh]

I like to use returns table (col_1 type, col_2 type) than casting returned data `select x,y from function_a() as (x type, y type).