Oracle: Get a query to always return exactly one row, even when there's no data to be found

Question

I have a query like this:

   select data_name
   into v_name
   from data_table
   where data_table.type = v_t_id

Normally, this query shou

Answer 1

If you always expect zero or one row then you can use a group function i.e.:

select dump(max(dummy)) from dual
where dummy = 'Not Found'

You will always get at least one row and a value of NULL in the case where the record is not found.