Question

I have the following script that I want output to the screen from.

CREATE OR REPLACE FUNCTION randomnametest() RETURNS integer AS $$
DECLARE
    rec RECORD;
BEGIN
    FOR rec IN SELECT * FROM my_table LOOP
        SELECT levenshtein('mystring',lower('rec.Name')) ORDER BY levenshtein;
    END LOOP;

    RETURN 1;
END;
$$ LANGUAGE plpgsql;

I want to get the output of the levenshein() function in a table along with the rec.Name. How would I do that? Also, it is giving me an error about the line where I call levenshtein(), saying that I should use perform instead.

Answer 1

If you want the output from a plpgsql function like the title says:

CREATE OR REPLACE FUNCTION randomnametest(_mystring text)
  RETURNS TABLE (l_dist int, name text) AS
$BODY$
BEGIN
    RETURN QUERY
    SELECT levenshtein(_mystring, lower(t.name)), t.name
    FROM   my_table t
    ORDER  BY 1;
END;
$$ LANGUAGE plpgsql;

• Declare the table with RETURNS TABLE.
• Use RETURN QUERY to return records from the function.
• Avoid naming conflicts between column names and OUT parameters (from the RETURNS TABLE clause) by table-qualifying column names in queries. OUT parameters are visible everywhere in the function body.
• I made the string to compare to a parameter to the function to make this more useful.

There are other ways, but this is the most effective for the task. You need PostgreSQL 8.4 or later.

For a one-time use I would consider to just use a plain query (= function body without the RETURN QUERY above).