I have removed "dbo.Centros.CodigoEmpresa = emp.CodigoEmpresa" and now works good but I'm not really sure about the consequences

SELECT dbo.CabecerasFacturas.CodigoEpisodio

FROM ...

Hi,

Thank you very much for your response.

I've tried the index creation but I get same result:

fast near 0 seconds

slow about 15 seconds.

Here you'll find new execution plans.

http://www.comoflipas.com/newSlowPlan.xml

http://www.comoflipas.com/newFastPlan.xml

Thanks again.