SELECT DISTINCT ON removes results
| От | Guyren Howe |
|---|---|
| Тема | SELECT DISTINCT ON removes results |
| Дата | |
| Msg-id | AF05A411-E3A8-4317-8D6B-D4D658991C8B@gmail.com обсуждение исходный текст |
| Ответы |
Re: SELECT DISTINCT ON removes results
Re: SELECT DISTINCT ON removes results |
| Список | pgsql-general |
Using 9.5, this query:
SELECT o.id,
a.number AS awb
FROM pt.orders o
LEFT JOIN (
SELECT DISTINCT ON ((string_agg(air_way_bills.number::text, ','::text)))
string_agg(air_way_bills.number::text, ','::text) AS number,
air_way_bills.order_id
FROM pt.air_way_bills
GROUP BY air_way_bills.order_id) a ON a.order_id = o.id
gives me null for awb. Removing the DISTINCT ON clause:
SELECT o.id,
a.number AS awb
FROM pt.orders o
LEFT JOIN (
SELECT string_agg(air_way_bills.number::text, ','::text) AS number,
air_way_bills.order_id
FROM pt.air_way_bills
GROUP BY air_way_bills.order_id) a ON a.order_id = o.id
where o.id = 2792;
gives me an awb. I'm confused about how this can be.
В списке pgsql-general по дате отправления: