I think he was saying that doing "ORDER BY UPPER(x)", where x is a
column of type INT, did something strange:

> " for numberical columns I will end up sorting textually: values 1,2,10 will 
> be sorted as 1,10,2."

On Sat, Aug 21, 2021 at 8:34 AM Rick Hillegas <rick.hille...@gmail.com> wrote:
>
> Some responses inline...
>
> On 8/21/21 8:03 AM, John English wrote:
> > On 20/08/2021 20:13, Rick Hillegas wrote:
> >> You could solve this problem with a custom character collation. See
> >> https://db.apache.org/derby/docs/10.15/devguide/cdevcollation.html
> >
> > Great!
> >
> >> If you don't need to sort the embedded numbers, then the simplest
> >> solution is to create a database which uses a case-insensitive sort
> >> order. See
> >> https://db.apache.org/derby/docs/10.15/devguide/tdevdvlpcollation.html
> >
> > I need to think a bit about whether I ever need case-sensitivity. I
> > suspect not, but I'll need to go through the tables, and if I can't
> > find any problems, this sounds like it might be the best solution.
> >
> > Assuming this is a viable solution, is there a way to convert a live
> > database from case-sensitive to case-insensitive (from
> > collation=TERRITORY_BASED:TERTIARY to
> > collation=TERRITORY_BASED:PRIMARY, if I understand correctly), which I
> > assume will involve rebuilding all the indexes?
> Unfortunately, you have to create a new database and copy your old data
> into the new database. I would recommend creating a fresh database which
> has the correct, case-insensitive collation. Then copy the old data into
> the new database using the foreign views optional tool. See
> https://db.apache.org/derby/docs/10.15/tools/rtoolsoptforeignviews.html
> >
> >> If you need to sort the embedded numbers too, then you have to supply
> >> a custom collator. See
> >> https://db.apache.org/derby/docs/10.15/devguide/tdevdvlpcustomcollation.html
> >
> > OK, this bit I didn't understand. Sometimes I want to sort on columns
> > of numbers, sometimes dates, sometimes strings. Is that what you mean
> > by needing to "sort the embedded numbers"?
> Or I don't understand your problem. I thought that you needed a string
> like abc2def to sort before abc10def. Sort order should be correct for
> numeric and date/time datatypes. It's just the character typed data
> which sorts incorrectly.
> >
> >> It's hard to imagine that you are the first person who needs the sort
> >> order you have described. Maybe a little googling will discover that
> >> someone has open-sourced a collator which does the right thing. If
> >> you can't find one but you end up writing your own, please consider
> >> open-sourcing it.
> >
> > OK, will do.
> >
> > Many thanks,
>
>

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