缓慢的SQL查询

Question

我的网页有问题。

它的运行速度非常慢，所以我在互联网上读到它可能是SQL的一个糟糕用法。所以我评论了更复杂的SQL行，并且它再次顺利运行。

我的问题是：'有没有办法让这个SQL请求“更轻”？

@companies = Company.where('tbl_companys.state = "enabled"') 

    @companies = @companies.includes(:benefit).where("tbl_benefits.end_date >= {Date.today}") 

    @companies = @companies.includes(:benefit).where(tbl_benefits: { state: 'enabled' }) 

    has_benef_gastro = false 

    has_benef_hote = false 

    has_benef_ent = false 

    until has_benef_gastro == true 

     @esta_gastro = (@companies.where('id_category = "2-gastronomia"').shuffle)[0] 

     @benefit_gastro = Benefit.where('id_company = ? AND end_date >= ? AND state = "enabled"', @esta_gastro.id_company, Date.today).first 

     if @benefit_gastro.nil? == false 

      has_benef_gastro = true 

     end 

    end 

    until has_benef_hote == true 

     @esta_hotelero = (@companies.where('id_category = "1-hoteleria"').shuffle)[0] 

     @benefit_hote = Benefit.where('id_company = ? AND end_date >= ? AND state = "enabled"', @esta_hotelero.id_company, Date.today).first 

     if @benefit_hote.nil? == false 

      has_benef_gastro = true 

     end 

    end 

    until has_benef_ent == true 

     @esta_ent = (@companies.where('id_category = "3-entretenimiento"').shuffle)[0] 

     @benefit_ent = Benefit.where('id_company = ? AND end_date >= ? AND state = "enabled"', @esta_ent.id_company, Date.today).first 

     if @benefit_ent.nil? == false 

      has_benef_gastro = true 

     end 

    end 

感谢您的帮助！

Answer 1

最后我做一个简单的SQL请求，所以我并没有与一些轨道的问题作斗争。

无论如何，谢谢！

Answer 2

您每次都在洗牌@esta_gastro，@esta_hotelero,@esta_ent和@benefit_变量，这没有任何意义。每做一次循环就需要多次新的数据库查询。

如果你想找到一个随机选择，只需在循环外创建你的集合，一次（在循环之外）洗牌，然后遍历这些集合，直到你满足你的标准。

例如：

@esta_gastro = @companies.where('id_category = "2-gastronomia"').shuffle 
@benefits = Benefit.where('end_date >= ? AND state = "enabled"', Date.today) 
@benefit_gastro = nil 
i = 0 
until !@benefit_gastro.blank? 
    @benefit_gastro = @benefits.where('id_company = ?', @esta_gastro[i].id_company).first 
    i += 1 
end 

编辑

如果整个目标是让@benefit_gastro定义，那么我甚至不认为你需要一个循环。您可以定义@esta_gastro集合，然后使用它找到所有对应的优点。由于@esta_gastro被打乱，你@benefit_gastro将是随机的：

@esta_gastro = @companies.where('id_category = "2-gastronomia"').shuffle 
@benefit_gastro = Benefit.where('end_date >= ? AND state = "enabled"', Date.today).where('id_company = ?', @esta_gastro.map(&:id)).limit(1)