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Ok, I get it. Good education!
Thank you very much, saved me a big headache! Edson Em 03/02/2013 03:06, Pavel Stehule escreveu: Hello 2013/2/3 Edson Richter <edsonrichter@xxxxxxxxxxx>:Hi! Assumptions: PostgreSQL 9.2.2, Win64, already run vacumm full freeze analyze. No problems in the database. I know there are 1247 records to be found. Why does these queries return different results: select count(*) from parcela where id not in (select parcela_id from cadastroservicoparcela); count -------- 0 select count(*) from parcela where not exists (select 1 from cadastroservicoparcela where parcela_id = parcela.id); count -------- 1247 I can't figure out, I did expect that the first one returns exactly same result! Could null values in cadastroservicoparcela.parcela_id affect the first query?sure http://stackoverflow.com/questions/2246772/whats-the-difference-between-not-exists-vs-not-in-vs-left-join-where-is-null Regards PavelThanks, Edson -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general |
