Re: SELECT * FROM foo OFFSET -1 LIMIT 1
От | Markus Bertheau |
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Тема | Re: SELECT * FROM foo OFFSET -1 LIMIT 1 |
Дата | |
Msg-id | 1119897697.7464.7.camel@localhost.localdomain обсуждение исходный текст |
Ответ на | Re: SELECT * FROM foo OFFSET -1 LIMIT 1 (Martín Marqués <martin@bugs.unl.edu.ar>) |
Ответы |
Re: SELECT * FROM foo OFFSET -1 LIMIT 1
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Список | pgsql-sql |
Dnia 27-06-2005, Mo o godzinie 14:17 -0300, Martín Marqués napisał(a): > How do you skip -1 rows? You redefine OFFSET to mean "where in the result set to start returning rows" and give -1 the meaning that I described above. Please don't ask me, where in the result set position -1 is. I've stumbled over this because I needed a query which given an id a result set like this: id txt pos 23 foo 0 11 bar 1 34 baz 2 13 xop 3 returns the previous and next rows relative to the given id, as ordered by the position). That would be 23 and 34 for 11, or NULL and 11 for 23. I'm basically determining the position of the middle row and then querying with offset pos-1 limit 1 and offset pos+1 limit 1. Offset for negative numbers means 0, as it seems. I think there is a sensible meaning for negative offset numbers and wondered, what arguments led to negative offsets being processed as 0 offset. Markus -- Markus Bertheau <twanger@bluetwanger.de>
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