{
  "columns": [
    "invoiceDate$year",
    "invoiceDate$month",
    "invoiceAmount",
    "invoiceAmount__prior",
    "invoiceAmount__diff",
    "invoiceAmount__ratio"
  ],
  "groupBy": [
    "invoiceDate$year",
    "invoiceDate$month"
  ],
  "orderBy": [
    "invoiceDate$year",
    "invoiceDate$month"
  ],
  "timeWindow": {
    "field": "invoiceDate$id",
    "grain": "month",
    "comparison": "yoy",
    "range": "[)",
    "value": [
      "2012-01-01",
      "2013-01-01"
    ],
    "targetMetrics": [
      "invoiceAmount"
    ]
  },
  "limit": 100
}