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


      when 'within'
        [r0, r1] = filter.range
        if typeof r0 is 'number' and typeof r1 is 'number'
          {
            type: 'javascript'
            dimension: filter.attribute
            function: "function(a){return a=~~a,#{r0}<=a&&a<#{r1};}"
          }
        else
          throw new Error("apply within has to have a numeric range")

      when 'not'
        {

}

aggregateToJS = {
  count: ['0', (a, b) -> "#{a} + #{b}"]
  sum:   ['0', (a, b) -> "#{a} + #{b}"]
  min:   ['Infinity',  (a, b) -> "Math.min(#{a}, #{b})"]
  max:   ['-Infinity', (a, b) -> "Math.max(#{a}, #{b})"]
}

correctSingletonDruidResult = (result) ->
