Null ordering in queries can be changed by settings?
От | Vincenzo Melandri |
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Тема | Null ordering in queries can be changed by settings? |
Дата | |
Msg-id | CAHSd9GfD6N80F75SgMuhLB0gd-Dqo77wVvR_QsqRJT4QOt1R0w@mail.gmail.com обсуждение исходный текст |
Ответы |
Re: Null ordering in queries can be changed by settings?
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Список | pgsql-novice |
I stepped into the same problem as this guy from 2005. Is this problem changed in the last 8 years? :) Can it be changed from settings now? > > unfortunately, standard 'nulls first/last' isn't supported yet. > to change behaviour you should use following statement: > select v_date, v_userid from votes order by v_date is not null desc, v_date desc > or, something like this: > select v_date, v_userid from votes order by coalesce(v_date, XXX) desc > where XXX is substituted by the date value that is smaller than any > other used in your table > > On 20/11/05, me(at)alternize(dot)com <me(at)alternize(dot)com> wrote: > > > > hi list > > > > coming from the MS-SQL Server world, we're migrating our applications slowly > > to pgsql 8.1. now we thumbled on a problem with different sort-order > > behaviours: > > > > we got a table with dated records: > > table: votes (v_userid, v_date) > > > > the v_date field can either be null or a date in the past. in mssql, sorting > > the table to list records in descending date-order > > > > select v_date, v_userid from votes order by v_date desc > > > > produces a list where first the records with dates are listed, and then the > > ones with nulls. in pgsql, the null-records are listed first before the > > date-records... how can this behaviour be changed? > > > > mssql: > > -------- > > 2005-11-05 3 > > 2005-11-01 4 > > 2005-09-10 1 > > null 2 > > null 5 > > > > > > pgsql: > > -------- > > > > null 2 > > null 52005-11-05 3 > > 2005-11-01 4 > > 2005-09-10 1 > > > > thanks in advance, > > thomas > -- > Best regards, > Nikolay -- Vincenzo. Imola Informatica Ai sensi del D.Lgs. 196/2003 si precisa che le informazioni contenute in questo messaggio sono riservate ed a uso esclusivo del destinatario. Pursuant to Legislative Decree No. 196/2003, you are hereby informed that this message contains confidential information intended only for the use of the addressee.
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