{
  "columns": [
    "sum(lineAmount) as totalAmount",
    "sum(salesQuantity) as quantity",
    "count(invoiceLineId) as lineCount"
  ],
  "slice": [
    {
      "field": "invoice$invoiceDate",
      "op": "[)",
      "value": [
        "2012-01-01",
        "2013-01-01"
      ]
    }
  ],
  "limit": 2
}