---
title: "BuildAggregate"
slug: "buildaggregate"
updated: 2024-12-02T18:27:19Z
published: 2024-12-02T18:27:19Z
canonical: "docs.datajet.app/buildaggregate"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.datajet.app/llms.txt
> Use this file to discover all available pages before exploring further.

# BuildAggregate

Creates a summary field by aggregating data from a foreign table onto a primary table.

| Key | Value(s) | Description |
| --- | --- | --- |
| method | "BuildAggregate" | Creates a summary field by aggregating data from a foreign table onto a primary table. |
| project | "#project#" |  |
| targetTable | "tableName" | required. Table on which to create the field. |
| source | "SourceTableName.SourceFieldName" | Required. Full name of field to aggregate. |
| function | "min/max/sum/count/avg" | - min - max - sum - count - avg |
| name | "FieldName" | Required. |
| dataSet | {} | Optional. If provided, source field will be filtered to include only records in the [dataset](/v1/docs/dataset). |
| overwrite | true/false | Optional. Default = false If true, existing field will be over-written. If false and field exists, error will be raised. |
| forceLong | true/false |  |

```json
{
  "method": "BuildAggregate",
  "project": "MyProject",
  "targetTable": "customer",
  "source": "transactions.profit",
  "overwrite": true,
  "name": "total profit",
  "function": "sum"
}
```

```json
{
  "method": "BuildAggregate",
  "project": "#project#",
  "targetTable": "",
  "source": "",
  "function": "",
  "name": "",
  "dataSet": {},
  "overwrite": false,
  "forceLong": false
}
```