Using Decode with "Long" datatypes

Question

Hi,
I want to use a select statement in a view which uses a decode function involving a "long" datatype. But doing some raises an error "Invalid datatypes". Is there a way around?
Anupam.

Answer 1

I'm a bit puzzled as to what it is you are trying to achieve (it has been an afternoon for vague requirements). Normally the sort of data that we would want to store in a LONG is ,er, long and therefore not susceptible to use in a DECODE. But it does not matter, because we can only manipulate LONGs in PL/SQL and that does not parse DECODE statements. We will have to use IF...ELSE constructs instead.
CREATE OR REPLACE FUNCTION l2v (pl in rowid)  RETURN VARCHAR2
AS
    ll LONG;
    rv VARCHAR2(20);        
BEGIN
   SELECT col1
   INTO ll
   FROM   T_LONG
   WHERE  rowid = pl;
   IF ll LIKE '%text%'
   THEN
      rv := 'yes!';
   ELSE
      rv :=  'noooo';
   END IF;
   RETURN rv;
END;
SQL> select l2v(rowid) from t_long;
L2V(ROWID)
yes!
yes!
SQL> You can use this function in a query. Note that it is doing a SELECT in its own right so this will not be a very performant solution if you build the view on a big table.
Cheers, APC