我的站内信的数据表大约有如下字段：
- id
- receiver_id
- sender_id
- is_read
- content
- created_at
eg. 如何取出 receiver_id = 1 的最近10个 sender_id ?
This topic created in 4226 days ago, the information mentioned may be changed or developed.
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1
xenme Oct 23, 2014
不是特别熟悉，大概应该这样：
select * from table where receiver_id=1 order by creted_at desc limit 10 |
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2
yangqi Oct 23, 2014
SELECT sender_id FROM 表 WHERE receiver_id=1 ORDER BY created_at DESC LIMIT 10;
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3
xenme Oct 23, 2014  1
可能sender有重复
select distinct sender_id,created_at from table where receiver_id=1 order by creted_at desc limit 10 |
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4
heaton_nobu Oct 23, 2014
我只想问问为什么不用主键id，而非要用created_at，难道不是新建的id就大吗
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5
WildCat OP @xenme 感谢。已经找到：
http://guides.rubyonrails.org/active_record_querying.html ```ruby query = Client.select(:name).distinct # => Returns unique names query.distinct(false) # => Returns all names, even if there are duplicates ``` 结贴。 |
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6
staticor Oct 23, 2014
用groupby 之类的对sender_id 去个重?
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7
msg7086 Oct 24, 2014 via iPhone 1
where.distinct.first 10
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