'What does the MD in Oracle's MDSYS stand for?
Oracle has an user called MDSYS.
What does the MD stand for? Something like 'main database'?
Solution 1:[1]
As deepak adviced, you might use distinct.
However, I guess you need to get maximum value from all records with the same user_id? Then you need to use sql to group values by user_id and selecting max from it. In Rails that might be like this. I can't tell you that it will work for sure because don't remember the output, believe it's array of hashes, it might throw the error that you're not using some other field:
Post.group(:user_id).max(:value)
it's SQL equalent:
SELECT user_id, MAX(value) FROM posts GROUP BY user_id
Sources
This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.
Source: Stack Overflow
| Solution | Source |
|---|---|
| Solution 1 | Ruslan K |