Rails Console find users by array of ids

问题:

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?

回答1:

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.

回答2:

you can use User.where(id: ids)

回答3:

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.

回答4:

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..

回答5:

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)

回答6:

you can use

   Users.where({ id: [1,2,3 ,4]})
 # SELECT * FROM users WHERE id IN (1,2,3,4)