Question

Given the following skeleton pl/pgsql function, how can I make it return true if the update was successful (something was actually updated) and false otherwise?

CREATE FUNCTION UpdateThingy(
    /* input parameters */
) RETURNS BOOLEAN AS $$
BEGIN
    UPDATE thingies SET /* blah blah */ WHERE /* blah blah */;
    RETURN true;
END;
$$ LANGUAGE plpgsql;

Currently this will always return true, even if no rows where updated. I want to return false in the case of no rows being affected by the update.

Answer 1

After the UPDATE, you can obtain the number of updated rows using GET DIAGNOSTICS or the FOUND status variable as described in the manual:

http://www.postgresql.org/docs/current/static/plpgsql-statements.html#PLPGSQL-STATEMENTS-DIAGNOSTICS