Re: Odd error when using UNION and COLLATE - Mailing list pgsql-hackers

On Wed, Jul 20, 2016 at 10:38 PM, Bruce Momjian <bruce@momjian.us> wrote:
> SELECT 'a-c' AS x UNION ALL SELECT 'ab' AS x ORDER BY x COLLATE "C";


::***> select 'a-c' COLLATE "C" AS x UNION ALL SELECT 'ab' AS x ORDER BY x ;
┌─────┐
│  x  │
├─────┤
│ a-c │
│ ab  │
└─────┘
(2 rows)


But I think I agree that it's surprising that the collate clause isn't
working in the ORDER BY on a column produced by a UNION. Certainly
that's where people usually want to put it.

--
greg