         {
           type: 'selector'
           dimension: filter.attribute
-          value: filter.value ? '' # In Druid null == '' and null is illegal
+          value: filter.value
         }
 
       when 'in'

            function(x) {
              x = Number(x);
              if(isNaN(x)) return null;
              x = #{floorExpresion};
              return x;
            }
            """


      when 'is'
        throw new Error("can not filter on specific time") if filter.attribute is @timeAttribute
        varName = @addToContext(context, filter.attribute)
        "#{varName} === '#{filter.value}'"

      when 'in'
        throw new Error("can not filter on specific time") if filter.attribute is @timeAttribute
        varName = @addToContext(context, filter.attribute)
        filter.values.map((value) -> "#{varName} === '#{value}'").join('||')

      when 'contains'
        throw new Error("can not filter on specific time") if filter.attribute is @timeAttribute
        varName = @addToContext(context, filter.attribute)
        "String(#{varName}).indexOf('#{filter.value}') !== -1"

      when 'not'
        "!(#{@filterToJSHelper(filter.filter, context)})"
