Re: cardinality()
| От | Tom Lane |
|---|---|
| Тема | Re: cardinality() |
| Дата | |
| Msg-id | 12505.1235926160@sss.pgh.pa.us обсуждение |
| Ответ на | Re: cardinality() (Andrew Dunstan <andrew@dunslane.net>) |
| Ответы |
Re: cardinality()
|
| Список | pgsql-hackers |
Andrew Dunstan <andrew@dunslane.net> writes:
> Grzegorz Jaskiewicz wrote:
>> 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?
>> Standart just says something like:
>> cardinality (a collection):
>> - The number of elements in that collection.
The standard doesn't have multi-dimensional arrays, so it's entirely
possible that somewhere in it there is wording that makes cardinality()
equivalent to the length of the first dimension. But I concur with
Andrew that this is flat wrong when extended to m-d arrays.
regards, tom lane
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