<ttina(at)access(dot)inet(dot)co(dot)th> writes:
> I use postgresql7.2 / redhat8
> I try "select 'X1'='X2' ;" and X1=(D button) in thai language, =
> X2=(8 button) in thai language
> result is true .This is wrong result!.
We've seen a lot of reports of bizarre behavior when you select a
database encoding that does not match the character set implied by
the locale setting you're using. Apparently strcoll() on many platforms
goes nuts when handed input that is not legally encoded according to
what it thinks the character set is.
In short: check your locale and your encoding.
regards, tom lane