How can Ransack be used to search for the last child record?

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To search for the last child record using Ransack, you can use the following code:

@q = Parent.ransack(params[:q])
@parents = @q.result(distinct: true).includes(:children).order('children.created_at DESC').first

Here, we are including the children association in the query and ordering the results by created_at in descending order. We then use the first method to retrieve the first record in the result set, which will be the last child record.