Improve performance of query with order by

Question

Hello,
I have a query with a necessary "order by" which lasts 24 seconds. The same query without the "order by" lasts 1 second.
How can I improve the performance of the query with "order by"?
Thank you very much.
The query is:
select distinct CC.acceso,CC.ext_acceso,TIT.TITULO_SALIDA
from (((Ocurrencias CT01 inner join
     palabras p0 on (CT01.cod_palabra = p0.cod_palabra and p0.palabra like 'VENEZUELA%' AND p0.campo = 'AUTOR')) INNER JOIN
     CENTRAL CC ON (CT01.ACCESO = CC.ACCESO AND CT01.EXT_ACCESO = CC.EXT_ACCESO))) inner join
     codtit ctt on (CC.acceso = ctt.acceso and CC.ext_acceso = ctt.ext_acceso) inner join
     titulos tit on (ctt.cod_titulo = tit.cod_titulo and ctt.portada = '1')
where CC.nivel_reg <> 's'
ORDER BY 3 ASC;

Answer 1

My guess is SQL Scratchpad is a GUI and is not returning all the rows but just the first screenful. Without any order by or distinct the database can start returning rows as soon as it finds the first one. With an order or distinct it needs to sort the rows so the first row can only be returned after the last row is retrieved.
Open a command line prompt and run
sqlplus
SQL> set timing on
SQL>And then run your queries.
If you still have a large discrepancy do this
SQL> set autotrace traceonly
SQL>And then run the queries and post the output.