Re: string_to_array with empty input

On Tue, Mar 31, 2009 at 5:48 PM, justin <justin(at)emproshunts(dot)com> 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