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Transformations

Summarising and Aggregating

Use these when you want totals, averages, or counts instead of showing every individual row.

---

Reduce — DF_REDUCE

Collapse all rows into a single summary row.

Use this when: you want one headline number per column — like total energy consumed, average temperature, or peak demand.

Available calculations: sum, avg, min, max, count, first, last.

Before

Code
[
  { "device": "AC-01", "kwh": 1.2, "temperature": 24 },
  { "device": "AC-02", "kwh": 1.7, "temperature": 33 },
  { "device": "AC-03", "kwh": 0.9, "temperature": 29 },
  { "device": "AC-04", "kwh": 2.4, "temperature": 35 }
]

After — total kWh and average temperature

Code
{ "total_kwh": 6.2, "avg_temperature": 30.25 }

Code
{
  "type": "DF_REDUCE",
  "config": {
    "calculations": [
      { "field": "kwh", "calc": "sum", "alias": "total_kwh" },
      { "field": "temperature", "calc": "avg", "alias": "avg_temperature" }
    ]
  }
}

---

Group By — DF_GROUP_BY

Summarise your data within groups, giving you one summary row per group.

Use this when: you want totals or averages broken down by a category — for example, total energy per floor, or average temperature per device type.

Before

Code
[
  { "floor": 1, "device": "AC-01", "kwh": 1.2 },
  { "floor": 1, "device": "AC-02", "kwh": 1.7 },
  { "floor": 2, "device": "AC-03", "kwh": 0.9 },
  { "floor": 2, "device": "AC-04", "kwh": 2.4 }
]

After — total kWh grouped by floor

Code
[
  { "floor": 1, "total_kwh": 2.9 },
  { "floor": 2, "total_kwh": 3.3 }
]

Code
{
  "type": "DF_GROUP_BY",
  "config": {
    "groupByFields": ["floor"],
    "aggregations": [
      { "field": "kwh", "calc": "sum", "alias": "total_kwh" }
    ]
  }
}