| From: | Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org> |
|---|---|
| To: | kyle(at)lahnakoski(dot)com, pgsql-bugs(at)lists(dot)postgresql(dot)org |
| Subject: | Re: BUG #17232: DISTINCT ON does not allow AS |
| Date: | 2021-10-16 14:59:15 |
| Message-ID: | 202110161459.hufnhzw4bosn@alvherre.pgsql |
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| Lists: | pgsql-bugs |
On 2021-Oct-15, PG Bug reporting form wrote:
> The following SQL has an unexpected syntax error
>
> SELECT DISTINCT ON (col) AS col, col2 FROM test
Well, the "ON (col)" part is not an output column -- it's just the
specification of the column that you want distinctness over. I suspect
you mean
SELECT DISTINCT ON (col) col AS col, col2 FROM test
... which looks like a pretty bogus thing to do, since you have no say
on *which* values of col2 are you going to get for each distinct value
of col. But ... it gives *some* result, at least.
--
Álvaro Herrera PostgreSQL Developer — https://www.EnterpriseDB.com/
"Pensar que el espectro que vemos es ilusorio no lo despoja de espanto,
sólo le suma el nuevo terror de la locura" (Perelandra, C.S. Lewis)
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