James Zhou <james(at)360data(dot)ca> writes:
> - *But their sorting order seems to be undefined. Can anyone comment
> the sorting rules?*
Well, it would depend on lc_collate, which you have not told us, and
it would also depend on how well your platform's strcoll() function
implements that collation; but you have not told us what platform this
is running on.
Most of the other behaviors you mention are also partly or wholly
dependent on which software you use with Postgres and whether you've
correctly configured that software. So it's pretty hard to answer
this usefully with only this much info.
regards, tom lane