Table name as a PostgreSQL function parameter

Question

I want to pass a table name as a parameter in a Postgres function. I tried this code:

CREATE OR REPLACE FUNCTION some_f(param character varying) RETURNS inte         


        

Answer 1

I know this is an old thread, but I ran across it recently when trying to solve the same problem - in my case, for some fairly complex scripts.

Turning the entire script into dynamic SQL is not ideal. It's tedious and error-prone work, and you lose the ability to parameterize: parameters must be interpolated into constants in the SQL, with bad consequences for performance and security.

Here's a simple trick that lets you keep the SQL intact if you only need to select from your table - use dynamic SQL to create a temporary view:

CREATE OR REPLACE FUNCTION some_f(_tbl varchar) returns integer
AS $$
BEGIN
    drop view if exists myview;
    execute format('create temporary view myview as select * from %s', _tbl);
    -- now you can reference myview in the SQL
    IF EXISTS (select * from myview where myview.id=1) THEN
     return 1;
    END IF;
    return 0;
END;
$$ language plpgsql;