declare


 n number;
 trace_error varchar2(100);
 
begin

select count(1) into n from ITEMS where item='ORACLE';

trace_error := ' ERROR  FOR COUNT';

select cost1 into n from ADMIN_COSTPL_OWNER.ITEM_COST_C10000 where item='ORACLE';

trace_error := trace_error || ', '|| ' ERROR FOR SELECT';


exception when no_data_found then

 dbms_output.put_line( trace_error);
end;

select 1 into n from ITEMS where item='ORACLE' and rownum =1;

SQL> set autotrace traceonly explain
SQL> select empno from emp group by empno having count(1) > 0;

Execution Plan
----------------------------------------------------------
Plan hash value: 1668054362

--------------------------------------------------------------------------------
| Id  | Operation             | Name   | Rows  | Bytes | Cost (%CPU)| Time     |
--------------------------------------------------------------------------------
|   0 | SELECT STATEMENT      |        |    14 |   182 |     1   (0)| 00:00:01 |
|*  1 |  FILTER               |        |       |       |            |          |
|   2 |   SORT GROUP BY NOSORT|        |    14 |   182 |     1   (0)| 00:00:01 |
|   3 |    INDEX FULL SCAN    | EMP_PK |    14 |   182 |     1   (0)| 00:00:01 |
--------------------------------------------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

   1 - filter(COUNT(*)>0)