{
  "columns": [
    "sum(invoiceAmount) as totalAmount",
    "count(invoiceId) as invoiceCount"
  ],
  "limit": 2,
  "slice": [
    {
      "field": "invoiceDate",
      "op": "[)",
      "value": [
        "2012-10-01",
        "2012-11-01"
      ]
    }
  ]
}