Rails: mysql error unknown column in sub query

I am implementing a search filter in my web app. using sub-queries like this:

tool = Tool.select('*, (select ROUND(AVG(ratings.rating)) from ratings where tool_id = tools.id AND rating_type = 2) as ratings, 

3956 * 2 * ASIN(SQRT(POWER(SIN(('+"#{params[:latitude]}"+' - abs(tools.latitude)) * pi()/180 / 2), 2) + COS('+"#{params[:latitude]}"+' * pi()/180 ) * COS(abs(tools.latitude) * pi()/180) * POWER(SIN(('+"#{params[:longtude]}"+' - abs(tools.longitude)) * pi()/180 / 2), 2) )) as  distance').where('user_id != ? AND pause_status =?', user_id, 0).order('distance asc')

    # =>delivery type only if delivery type is 1
    if params[:search].present? && !params[:search].nil?
      tool = tool.where('title LIKE ? OR description LIKE ?', "%#{params[:search]}%","%#{params[:search]}%")
    end

    # =>Category search
    if params[:category_id].present? && !params[:category_id].nil?
      tool = tool.where('category_id =?', params[:category_id])
    end

    # =>price range
    if params[:max_price].present? && params[:min_price].present? && !params[:max_price].nil? && !params[:min_price].nil?
      tool = tool.where('price >= ? AND price <= ?', params[:min_price].to_f, params[:max_price].to_f)
    end

    # => filter availability
    if params[:availability].present? && !params[:availability].nil?
      if params[:availability].to_i == 2
        tool = tool.where('available_type =?', 2) #=> weekend
      elsif params[:availability].to_i == 1
        tool = tool.where('available_type =?', 1) # => weekdays
      end
    end

    if params[:rating].present? && !params[:rating].nil?
      tool = tool.having('ratings > 5')
    end


    if params[:delivery_type].present? && !params[:delivery_type].nil?
      if params[:delivery_type].to_i == 0
        tool = tool.where('delivery_type = ?', 0)
      end
    end

    if tool.empty?
      return []
    else
      tool_array = []
      tool.each do |t|
        tool_hash = {}
        tool_hash['id'] = t.id
        tool_hash['title'] = t.title
        tool_hash['latitude'] = t.latitude
        tool_hash['longitude'] = t.longitude
        tool_hash['attachment'] = Image.get_single_attachment(t.id)
        tool_array.push(tool_hash)
      end
      return tool_array
    end

when I pass rating parameter it print the query like this:

SELECT COUNT(*) FROM `tools` WHERE (user_id != 3 AND pause_status =0) HAVING (ratings > 5)"

and without rating parameter:

SELECT *, (select ROUND(AVG(ratings.rating)) from ratings where tool_id = tools.id AND rating_type = 2) as ratings, 3956 * 2 * ASIN(SQRT(POWER(SIN((30.657797735213 - abs(tools.latitude)) * pi()/180 / 2), 2) + COS(30.657797735213 * pi()/180 ) * COS(abs(tools.latitude) * pi()/180) * POWER(SIN((76.7327738833397 - abs(tools.longitude)) * pi()/180 / 2), 2) )) as  distance FROM `tools` WHERE (user_id != 3 AND pause_status =0) ORDER BY distance asc"

and I a error like this in my having clause:

"error": "Mysql2::Error: Unknown column 'ratings' in 'having clause': SELECT COUNT(*) FROM `tools` WHERE (user_id != 3 AND pause_status =0) HAVING (ratings > 5)",
  "code": 301

and if I comment the each loop it works. Please tell where I am doing wrong.