Question

Check is a model that has the attributes product_line_id and date.

I have four instances of the Check model. They all have different dates. Two belong to product line 1 and the other two belong to product line 2.

How do I call a query on the Check model to return one check for each product line having the greatest date for for that product line?

Answer 1

I agree with noodl: you shouldn’t be using date as the column’s name.

Check.select("id, product_line_id, max(date) as greatest_date").group(:product_line_id)