So I have an array of user ids. Is there a way in rails console to query all of these user's with the array
something like
ids = [1, 2, 3, 4]
users = User.find(ids)
and have it return all 4 users?
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2It does work. You can pass an array of IDs to the model's find method and, provided they are all existing IDs, you will get back an array of user's for those IDs.DiegoSalazar– DiegoSalazar2014-01-29 15:52:03 +00:00Commented Jan 29, 2014 at 15:52
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Didn't realized this worked... haha. Should have tested it.Seth– Seth2014-01-29 16:19:38 +00:00Commented Jan 29, 2014 at 16:19
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6 Answers
For an array, you can use one of these:
# Will raise exception if any value not found
User.find( [1,3,5] )
# Will not raise an exception
User.find_all_by_id( [1,3,5] ) # Rails 3
User.where(id: [1,3,5]) # Rails 4
If you happen to be using a range, you can use these:
# Will raise exception if any value not found
User.find((1..4).to_a) #same as User.find([1,2,3,4])
# Will not raise an exception
User.find_all_by_id(1..4) # Rails 3
User.where(id: 1..4) # Rails 4
As @diego.greyrobot notes in a comment, a range causes a SQL BETWEEN clause, whereas an array causes a SQL IN clause.
Don't use User.find_by_id() -- It will only return one record, no matter how may IDs you pass in.
answered Jan 29, 2014 at 15:45
Grant Birchmeier
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7 Comments
Seth
My actual array isn't from 1 - 4. The ids are sporadic for example 122, 323, 451. Can I still achieve that?
DiegoSalazar
There's a few inaccuracies here: User.find((1..4).to_a) will make it work. And: 1..4 creates a Range not an Array.
DiegoSalazar
Yes, it's important to note that passing in a range (User.find_all_by_id(1..4)) will execute a sql BETWEEN clause, whereas passing in an array will do a sql IN statement.
Grant Birchmeier
Edited to add Rails 4 preferred versions.
Neeraj
.find returns
Array. Whereas .where returns ActiveRecord::Relation |
you can use User.where(id: ids)
Use splash operator:
ids = [1, 2, 3, 4]
users = User.find(*ids)
Note that it will raise an exception if it fails to find any of the users.
3 Comments
Grant Birchmeier
Ooh, that's neat. I didn't know about that one.
DiegoSalazar
You don't need to splat it, find takes an array just fine.
Grant Birchmeier
I'm finding that too. The splat does nothing.
This is work for me...
ids = [1, 2, 3, 4]
users = User.find(ids)
users = User.find(*ids)
users = User.find_all_by_id(ids)
All are working..
Comments
What you're doing is supposed to work when all the ids exist.
The reason you might be seeing an exception is because at least one of those ids does not exist in the database.
Instead, you want to use find_all_by_id if you don't want to get an exception:
User.find_all_by_id([1, 2, 3, 4])
# Does the following sql:
User Load (0.4ms) SELECT `users`.* FROM `users` WHERE `users`.`id` IN (1, 2, 3, 4)
Comments
you can use
Users.where({ id: [1,2,3 ,4]})
# SELECT * FROM users WHERE id IN (1,2,3,4)
1 Comment
psubsee2003
I would encourage you to expand on this answer to provide some explanation. An answer that is all code doesn't really provide a lot of information to other users that are unfamiliar with the concepts in the question.