Question

We currently have a stored proc that needs to do the following:
If Query1 returns any results open a sys_refcursor cursor for that and return it back
else
open a cursor for Query2

Currently we are doing a count(*) on the from and where clauses of Query1 and use the count in a if-else stmt. However, this causes query1 to be executed twice. Is there a way to optimize this?

Answer 1

Open the cursor for query1 & perform the real query. Wrap it in a BEGIN .. END block & catch the no data found exception.

BEGIN

-- query1 code

-- return data

EXCEPTION
   WHEN NO_DATA_FOUND THEN
   NULL;

BEGIN
-- query2 code

-- return data

END;

The query2 code will get run when there’s no data returned by query1.