I wrote:
> 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.
I poked around in the SQL:2008 draft a bit. AFAICT the most precise
statement about cardinality() is in 6.27 <numeric value function>:
<cardinality expression> ::= CARDINALITY<left paren> <collection value expression> <right paren>
7) The result of <cardinality expression> is the number of elements of the result of the <collection value
expression>.
Now the standard is only considering 1-D arrays, but I fail to see any
way that it could be argued that the appropriate reading of "number of
elements" for a multi-D array is the length of the first dimension.
So I think Andrew is right and we need to fix our implementation of
cardinality() while we still can.
regards, tom lane