I found answer on https://www.unicode.org/reports/tr35/tr35-collation.html and https://cldr.unicode.org/index/bcp47-extension
On Wed, May 25, 2022 at 1:52 PM jian he <jian.universal...@gmail.com> wrote: > > code from > https://www.postgresql.org/message-id/flat/5e756dd6-0e91-d778-96fd-b1bcb06c161a%402ndquadrant.com > >> DROP DATABASE IF EXISTS dbicu; >> CREATE DATABASE dbicu LOCALE_PROVIDER icu LOCALE 'en_US' ICU_LOCALE >> 'en-u-kf-upper' template 'template0'; >> \c dbicu >> CREATE COLLATION upperfirst (provider = icu, locale = 'en-u-kf-upper'); >> CREATE TABLE icu(def text, en text COLLATE "en_US", upfirst text COLLATE >> upperfirst); >> INSERT INTO icu VALUES ('a', 'a', 'a'), ('b','b','b'), ('A','A','A'), >> ('B','B','B'); >> SELECT def AS def FROM icu ORDER BY def; >> SELECT def AS en FROM icu ORDER BY en; >> SELECT def AS upfirst FROM icu ORDER BY upfirst; >> SELECT def AS upfirst_explicit FROM icu ORDER BY en COLLATE upperfirst; >> SELECT def AS en_x_explicit FROM icu ORDER BY def COLLATE "en-x-icu"; >> > > - trying to replicate the above quoted command. > - So I don't know * ICU_LOCALE 'en-u-kf-upper' *the *u *and the *kf *refer > to? > > Even I followed > https://unicode-org.github.io/icu/userguide/locale/#the-locale-concept > > 1. Language code > 2. Script code > 3. Country code > 4. Variant code > 5. Keywords > > So which website can I get the info about the "kf" and "u". > > -- > I recommend David Deutsch's <<The Beginning of Infinity>> > > Jian > > > -- I recommend David Deutsch's <<The Beginning of Infinity>> Jian
