Re: Different type of query
| От | Steve Crawford |
|---|---|
| Тема | Re: Different type of query |
| Дата | |
| Msg-id | 48502109.4090300@pinpointresearch.com обсуждение исходный текст |
| Ответ на | Re: Different type of query (PostgreSQL Admin <postgres@productivitymedia.com>) |
| Ответы |
Tsearch
|
| Список | pgsql-sql |
> I would like to have multiple values nutrient_no:
> ndb_no | nutrient_no | nutrient_value
> --------+-------------+----------------
> 13473 | 203 | 24.18
> 13473 | 204 | 15.93
> 13473 | 205 | 0
> 13473 | 207 | 1.1
> 13473 | 208 | 247
> 13473 | 221 | 0
>
> I'm thinking:
> select nutrient_no, nutrient_value from nutrient_data where ndb_no =
> 13473 and (nutrient_no = '203' or nutrient_no = '204' or nutrient_no =
> 208);
>
Depending on what you are trying to achieve:
Particular ndb_no and multiple nutrient_no, note that output of ndb_no
is superfluous as it is always the same:
select nutrient_no, nutrient_value from nutrient_data where ndb_no =
13473 and nutrient_no in ('203', '204','208');
Size limited list (say top 5 nutrient values) for a given ndb_no:
select nutrient_no,nutrient_value from nutrient_data where ndb_no =
13473 order by nutrient_value limit 5;
Cheers,
Steve
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