Ruby `除了'；：不支持的情况除外（Sequel:：InvalidOperation）

我在尝试运行sinatra应用程序时遇到错误。我试着用谷歌搜索，结果什么也没找到。如果你们能提供任何关于如何修复它或我做错了什么的建议，这将是非常有帮助的

出错代码的一部分

   def logTownDeltas!(newDate)
        deltas = []

        oldTowns = @db[:towns].filter { data_timestamp < newDate }
        currentTowns = @db[:towns].except(oldTowns)

        destroyedTownIDs = oldTowns.select(:town_id).except(currentTowns.select(:town_id)).collect { |d| d[:town_id] }
        createdTownIDs = currentTowns.select(:town_id).except(oldTowns.select(:town_id)).collect { |c| c[:town_id] }

        alteredTowns = Hash.new
        currentTowns.each { |town|

        }

试试这个：

def logTownDeltas!(newDate)
  deltas = []
  currentTowns = @db[:towns].filter { data_timestamp >= newDate }

  destroyedTownIDs = @db[:towns].select(:town_id).filter { data_timestamp < newDate }.collect { |d| d[:town_id] }
  createdTownIDs = @db[:towns].select(:town_id).filter { data_timestamp >= newDate }.collect { |c| c[:town_id] }

        alteredTowns = Hash.new
        currentTowns.each { |town|

        }

def logTownDeltas！（新日期）
三角洲=[]
currentTowns=@db[：towns]。筛选器{data\u timestamp>=newDate}
destroyedTownIDs=@db[：towns]。选择（：town_id）。筛选{data_timestamp=newDate}。收集{c | c[：town_id]}
alteredTowns=Hash.new
currentTowns.each{|镇|
}

我使用的是MySql数据库MySql除了语法外不支持其他语法。看到了吗？是的，我看到了，在我现在发布了这篇文章之后，我正试图找出当我将它改为开始获取C:/Ruby22/lib/ruby/gems/2.2.0/gems/sequel-4.29.0/lib/sequel/adapters/mysql时，我将得到什么来代替except。rb:175:'query'：mysql:：Error:Subquery返回超过1行（sequel:：DatabaseError）非常感谢您的帮助我遇到了一个问题我的下一行代码在找到destroyedTownIDs和createdTownIDs后它输入数据库仅destroyedTownIDs有0 pop，然后执行createdTownIDs但现在它为前一天数据库中的每个城镇创建0 pop数据。我把输入数据的代码放在上面的数据库中

 destroyedTownIDs.each { |d|
            t = oldTowns.filter(:town_id => d).first
            @db[:town_deltas].insert(
                :happened_at => newDate,
                :town_id => d,
                :owner_id => t[:owner_id],
                :name => t[:name],
                :population => 0,
                :is_capital => 0,
                :is_alliance_capital => 0)
        }


        createdTownIDs.each { |c|
            t = currentTowns.filter(:town_id => c).first
            @db[:town_deltas].insert(
                :happened_at => newDate,
                :town_id => c,
                :owner_id => t[:owner_id],
                :name => t[:name],
                :population => t[:population],
                :is_capital => t[:is_capital],
                :is_alliance_capital => t[:is_alliance_capital])
        }

def logTownDeltas!(newDate)
  deltas = []
  currentTowns = @db[:towns].filter { data_timestamp >= newDate }

  destroyedTownIDs = @db[:towns].select(:town_id).filter { data_timestamp < newDate }.collect { |d| d[:town_id] }
  createdTownIDs = @db[:towns].select(:town_id).filter { data_timestamp >= newDate }.collect { |c| c[:town_id] }

        alteredTowns = Hash.new
        currentTowns.each { |town|

        }