pl/pgSQL variable substitution - Mailing list pgsql-general

Hi,

I'm creating a pl/pgSQL function that returns a table that has a column name which is the same as a PostgreSQL
reserved. In the below example a have returning table with a column called 'desc': 

CREATE OR REPLACE FUNCTION bad_func() RETURNS TABLE (bar INTEGER, "desc" VARCHAR(100)) AS $$
BEGIN
    RETURN QUERY
        SELECT foo.bar, foo."desc"
        FROM foo
        ORDER BY foo."desc" DESC;
END;
$$ LANGUAGE plpgsql;

When I have a query that uses DESC reserved word within the function the following variable substitution occurs:

ERROR:  syntax error at or near "$1"
LINE 1:  SELECT foo.bar, foo."desc"   FROM foo."desc" ORDER BY  foo."desc"   $1
                                                                             ^

In my case I really would like to keep the table names i.e. no '_' etc.

I can think of a few options to do this with varying levels of syntactic sugar:

1) Use RETURNS SETOF RECORD instead of RETURNS TABLE:

CREATE OR REPLACE FUNCTION test1() RETURNS SETOF RECORD AS $$
BEGIN
    RETURN QUERY
        SELECT
            audit_id,
            "desc"
        FROM crs_sys_code
        ORDER BY "desc" DESC ;
END;
$$ LANGUAGE plpgsql;

Not a great interface because you have to declare the return record column names and types i.e.:

SELECT * FROM test1() AS (id INTEGER, "desc" TEXT);

2) Create a composite type for the table row and use RETURNS SETOF:

CREATE OR REPLACE FUNCTION test2() RETURNS SETOF table_type AS $$
BEGIN
    RETURN QUERY
        SELECT
            audit_id,
            "desc"
        FROM crs_sys_code
        ORDER BY "desc" DESC;
END;
$$ LANGUAGE plpgsql;

Better, but you have to create a type specifically for the function.

3) CREATE a SQL language wrapper around the example in 1):

CREATE OR REPLACE FUNCTION test3() RETURNS TABLE (id INTEGER, "desc" TEXT) AS $$
    SELECT * FROM test2() AS (id INTEGER, "desc" TEXT);
$$ LANGUAGE sql;

Nice interface, but now I need to manage two functions...


Does anyone have any other suggestions here?

Is this pl/pgSQL variable substitution seen as a feature of PostgreSQL, or a hangover from when PostgreSQL didn't
supportnamed function parameters? Really drives me crazy when naming variables in pl/pgSQL! 

Best Regards,
Jeremy
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