Greg Stark wrote: <blockquote cite="mid:4136ffa0903311006v15eb3a25xf3fa94a8ca089fd6@mail.gmail.com" type="cite"><pre
wrap="">OnTue, Mar 31, 2009 at 5:48 PM, justin <a class="moz-txt-link-rfc2396E"
href="mailto:justin@emproshunts.com"><justin@emproshunts.com></a>wrote: </pre><blockquote type="cite"><pre
wrap="">Butconsider 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[] </pre></blockquote><pre wrap="">
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. </pre></blockquote><br /> I disagree. Casting a string to something else can be a very error prone to begin
with.<br /> Having string_to_array() to deal with that possibility is out of its scope IMHO.<br /><br /> Consider
this. I have intelligent part numbers that need to be split apart to simplify searching and do math with. <br /><br
/>string_to_array(' F-2500-50 ', '-' ) ::int[]<br /><br /> Still fails with an error as expected. what is the
differencebetween ' ' and 'F' <br /><br /> So before doing any thing a test needs to be done to verify the contents,
soit can be casted to something else.<br />
