Re: Different type of query
От | Mark Roberts |
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Тема | Re: Different type of query |
Дата | |
Msg-id | 1213210572.9666.98.camel@localhost обсуждение исходный текст |
Ответ на | Re: Different type of query (PostgreSQL Admin <postgres@productivitymedia.com>) |
Ответы |
Re: Different type of query
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Список | pgsql-sql |
On Wed, 2008-06-11 at 14:41 -0400, PostgreSQL Admin wrote: > 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); > > > Now is that the most efficient SQL query? > > Thanks, > J It seems that you'd want to do something like: select nutrient_no, nutrient_value from nutrient_data where ndb_no = 13473 and nutrient_no in (203, 204, 208..) You could also grab the most significant 8 nutrients by doing something like: select nutrient_no, nutrient_value from nutrient_data where ndb_no = 13473 order by nutrient_value desc limit 8 -Mark
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