How to change an order result by locale on Heroku Postgres?

Issue

I want to change an order result by local, but it appears that LC_COLLATE is not allowed to change.

Resolution

Example of en_US.UTF-8(default) to ja_JP.utf8:

You should be able to create the collation with

CREATE COLLATION ja_JP (locale = 'ja_JP.utf8');

Then:

ALTER TABLE foo ALTER COLUMN title TYPE VARCHAR COLLATE ja_JP;