Re: cardinality()
От | Grzegorz Jaskiewicz |
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Тема | Re: cardinality() |
Дата | |
Msg-id | 625B8158-CCE7-4D84-ACE1-6D1964145018@pointblue.com.pl обсуждение исходный текст |
Ответ на | cardinality() (Andrew Dunstan <andrew@dunslane.net>) |
Ответы |
Re: cardinality()
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Список | pgsql-hackers |
On 1 Mar 2009, at 00:52, Andrew Dunstan wrote: > > We seem to have acquired a cardinality() function with almost no > discussion, and it has semantics that are a bit surprising to me. I > should have thought cardinality(array) would be the total number of > elements in the array. Instead, it seems it is a synonym for > array_length(array,1). Is that *really* what the standard says? any difference between array_upper(array,1), and cardinality ? Standart just says something like: cardinality (a collection): - The number of elements in that collection. - Those elements need not necessarily have distinct values. - The objects to which this concept applies includes tables and the values of collection types.
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