CODEWITHSUNDEEP
ruby-on-railsruby-on-rails-4plsqlrails-activerecord
Praveen George
Praveen George

Reputation: 9715

Rails : How to merge or join two active record collection?

In my customer controller I have two collection as follows:

The first one is to get a collection of Customers where the expiryDate column is having a valid date, as follows :

@customer_with_expirydate = Customer.where.not(expiryDate: nil)

The second one is to get a collection of Customers where the expiryDate column is nil or nnot present, as follows :

@customer_no_expirydate = Customer.where(expiryDate: nil)

Now I want to display the combined result of these two collection into a table structure, here one condition is like after listing all customers with expiryDate only customers without expiry need to be listed.

I need something like the following:

@all_customers = @customer_with_expirydate + @customer_no_expirydate

The important thing is that customers without expiry should be appended last.

Upvotes: 0

Views: 2938

Answers (3)

Hieu Pham
Hieu Pham

Reputation: 6707

Let sort the customers by db query, it is more efficient than using array appending:

@ordered_customers = Customer.order('expiryDate DESC NULLS LAST')

So the customer with expiryDate = nil will be at the end of your result!

Upvotes: 2

user2638707
user2638707

Reputation: 316

@Praveen Answer you had already given:

@all_customers = @customer_with_expirydate + @customer_no_expirydate

Returns All customers who has expiry date and then customers who does not have expiry date.

similarly:

@all_customers = @customer_no_expirydate + @customer_with_expirydate

Returns All customers who does not have expiry date and then customers who has expiry date.

Then you can loop @all_customers inside the table.

And if you can use only one query for this, then you should use:

@all_customers = Customer.order(expiryDate: :desc)

Upvotes: 2

aliibrahim
aliibrahim

Reputation: 1965

How about doing something simple with just one query? Something like: 

@all_customers = Customer.order(expiryDate: :desc)

Upvotes: 3

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