On Tue, Mar 31, 2009 at 5:48 PM, justin <justin@xxxxxxxxxxxxxxx> wrote:
>
> But consider this fails also
>
> select string_to_array('1, , 3', ',' )::int[] => ERROR: invalid input
> syntax for integer: " "
>
> yet this works
>
> select string_to_array('1, 2, 3',',')::int[]
Sure, and the analogous pair string_to_array(' ',',')::int[] and
string_to_array('1 ',',')::int[] behave similarly.
The point is that '' could represent no items or one empty string. We
get to pick which one and in any use case where the string was a list
of objects it's almost certainly intended to be an empty list. And
databases are almost always processing lists of things.
I think the only use case where you want it to be a singleton list of
an empty string is when you're doing string parsing such as building a
lexer or something like that, which is isn't a typical use for sql
code.
--
greg
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