I have a simple question, but I’m not able to figure out the syntax …

I want to assign the max value of the field “val” to the variable maxVal

{
  "data": {
    "values": [
      {"rowgroup": "I", "segment": "C", "val": 2000000},
      {"rowgroup": "I", "segment": "B", "val": 7000000},
      {"rowgroup": "II", "segment": "A", "val": 4000000},
      {"rowgroup": "II", "segment": "B", "val": 1000000},
      {"rowgroup": "II", "segment": "D", "val": 2000000}
    ]
  },
"params":[
{"name":"maxVal", ...}
]

}

Thank you very much.