activerecord query

gistfile1.txt

# params[:category] is an array of categories like ['tops, 'bottoms', 'outerwear'].
# For each category I have a corresponding array of sizes like ['M', 'L'].
# params[category] gives the sizes for the category.
#I want to return the given sizes in each category so I've created this loop.

# However I don't know how to merge the queries together. I think I'm supposed to use .merge but I'm not sure what to define @listings as so I can call .merge on it in the loop.

@listings = []
params[:category].each do |category|
  @listings += Listing.where(category: category, size: params[category], designer: params[:designer], sold: nil).include(:photos).page(params[:category_page]).per(@perpage)
end

params hash

{"category"=>["tops", "bottoms", "outerwear", "raw denim", "suiting", "accessories", "footwear"], "designer"=>["3sixteen", "Alexander McQueen", "APC", "Band of Outsiders", "dfv", "dfvd", "dvf", "fglkbnf", "fgn", "J Crew", "lkndfv", "Naked and Famous", "RRL", "rtgrt", "Saturdays", "some designer", "tester", "Undercover", "Visvim", "wings and horns"], "tops"=>["31", "M"], "bottoms"=>["28x32", "32"], "outerwear"=>["L"], "rawdenim"=>["31", "34"], "footwear"=>["fgnhg"], "ajax"=>"1", "controller"=>"home", "action"=>"index"}