CODEWITHSUNDEEP
ruby-on-railsruby-on-rails-5
Petros Kyriakou
Petros Kyriakou

Reputation: 5343

How to count total number of values as they appear inside a table

I have a table called Sales. And i have a field called plate_number corresponding to a single car.

How can i find the total number of instances of each car in db.

E.g [ [plate_number1, 10 times found], [plate_number2, 5 times found] ]

I tried using

Sale.map(&:plate_number).count and Sale.pluck(:plate_number)

but these just do a simple count of that column

any help appreciated

Upvotes: 1

Views: 846

Answers (2)

Petros Kyriakou
Petros Kyriakou

Reputation: 5343

This is a second solution i found for anyone who is interested

Sale.all.group_by { |ss| ss["plate_number"] }.map { |k,v| [k, v.length] }

Upvotes: 0

neydroid
neydroid

Reputation: 1951

You need to use count with group like:

Sale.group(:plate_number).count

This will return a hash with each plate_number and the count of occurrences.

# => { 'plate1' => 5, 'plate2' => 2 }

Upvotes: 4

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