CODEWITHSUNDEEP
ruby-on-railsrubyactiverecord
liquorishe
liquorishe

Reputation: 67

Extract average values of multiple columns via ActiveRecord

I have a Grade model from which I need to pull the averages of two columns - accuracy and time. I’m using the following query to get both values together instead of querying the model twice.

Grade.where(student_id: 25).pluck('avg(accuracy), avg(time)')

I get two values alright, but they are in the following format which I do not understand:

[[#<BigDecimal:7f9c5a890410,’8.0’,9(18)>, #<BigDecimal:7f9c5a8903c0,’10.0’,9(18)>]]

How do I extract only the values that I need from this? i.e. avg_accuracy = 8.0 and avg_time = 10.0

I'm new to Ruby, Rails, ActiveRecord. I appreciate the help.

Upvotes: 0

Views: 1305

Answers (1)

Ursus
Ursus

Reputation: 30056

grades = Grade.where(student_id: 25, class_id: 123).pluck('avg(accuracy), avg(time)').first

Should get

[#<BigDecimal:7f9c5a890410,’8.0’,9(18)>, #<BigDecimal:7f9c5a8903c0,’10.0’,9(18)>]

and now convert them to simple floats.

grades.map!(&:to_f)

should get

[8.0, 10.0]

Upvotes: 6

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