When you use this function in a query, it determines the difference in dates between the two specified column in the specified dataset.

For more information on using query functions and operators in a REST API request, see Queries. For an end-to-end description of how to create a query, see Creating a Query.

The codeblock example below calculates the differences in dates between the entries in the Datetime and Datetime2 columns of the earthquake dataset, whose {DATASET_ID} is 90af668484394fa782cc103409cafe39. Note that this dataset does not actually have a second Datetime column.

{
  "version": 0.3,
  "dataset": "90af668484394fa782cc103409cafe39",
  "namespace": {
    "date_difference": {
      "source": ["datetime","datetime2"],
      "apply": [{
        "fn": "date_diff", 
        "type": "transform",   
        "params": ["month"]
      }]
    }
  },
  "metrics": ["date_difference"],
}

When you submit the above request, the response includes an HTTP status code and a JSON response body.

For more information on the HTTP status codes, see HTTP Status Codes.

For more information on the elements in the JSON structure in the response body, see Query.