Greg Stark wrote:
On Tue, Mar 31, 2009 at 5:48 PM, justin <jus...@emproshunts.com> wrote:But consider this fails alsoselect 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. I disagree. Casting a string to something else can be a very error prone to begin with. Having string_to_array() to deal with that possibility is out of its scope IMHO. Consider this. I have intelligent part numbers that need to be split apart to simplify searching and do math with. string_to_array(' F-2500-50 ', '-' ) ::int[] Still fails with an error as expected. what is the difference between ' ' and 'F' So before doing any thing a test needs to be done to verify the contents, so it can be casted to something else. |
- Re: [GENERAL] string_to_array with empty input Tom Lane
- Re: [GENERAL] string_to_array with empty input Justin
- Re: [HACKERS] [GENERAL] string_to_array with empty i... David E. Wheeler
- Re: [GENERAL] string_to_array with empty input Greg Stark
- Re: [HACKERS] [GENERAL] string_to_array with empty i... Brendan Jurd
- Re: [HACKERS] [GENERAL] string_to_array with emp... Sam Mason
- Re: [GENERAL] string_to_array with empty inp... Greg Stark
- Re: [HACKERS] [GENERAL] string_to_array with... justin
- Re: [GENERAL] string_to_array with empty... Greg Stark
- Re: [GENERAL] string_to_array with ... justin
- Re: [GENERAL] string_to_array w... Greg Stark
- Re: [GENERAL] string_to_array w... justin
- Re: [GENERAL] string_to_array with empty input Greg Stark
- Re: [GENERAL] string_to_array with empty inp... Sam Mason
- Re: [HACKERS] [GENERAL] string_to_array ... David E. Wheeler
- Re: [GENERAL] string_to_array with empty... Greg Stark
- Re: [GENERAL] string_to_array with ... Sam Mason
- Re: [GENERAL] string_to_array with empty... justin