# JSONPATHARRAYDEFAULTEMPTY

Extracts an array from `jsonField` based on `'jsonPath'`, the result type is inferred based on JSON value. Returns empty array for null or parsing error. This function can only be used in an [ingestion transformation function](https://docs.pinot.apache.org/release-0.11.0/developers/advanced/ingestion-level-transformations).

## Signature

> JSONPATHARRAYDEFAULTEMPTY(jsonField, 'jsonPath')

| Arguments    | Description                                                                                            |
| ------------ | ------------------------------------------------------------------------------------------------------ |
| `jsonField`  | An **Identifier**/**Expression** contains JSON documents.                                              |
| `'jsonPath'` | Follows [JsonPath Syntax](https://goessner.net/articles/JsonPath/) to read values from JSON documents. |

{% hint style="warning" %}
**`'jsonPath'`**\` is a literal. Pinot uses single quotes to distinguish them from **identifiers**.\
\
You can use the [Jayway JsonPath Evaluator Tool](https://jsonpath.herokuapp.com/) to test JSON expressions before you import any data.
{% endhint %}

## Usage Examples

The usage examples are based on extracting fields from the following JSON document:

```json
{
  "data": {
    "name": "Pete",
    "age": 24,
    "subjects": [
      {
        "name": "maths",
        "homework_grades": [80, 85, 90, 95, 100],
        "grade": "A",
        "score": 90
      },
      {
        "name": "english",
        "homework_grades": [60, 65, 70, 85, 90],
        "grade": "B",
        "score": 70
      }
    ]
  }
}
```

| Expression                                                                    | Value                  |
| ----------------------------------------------------------------------------- | ---------------------- |
| `JSONPATHARRAYDEFAULTEMPTY(myJsonRecord, '$.subjects[*].name')`               | `["maths", "english"]` |
| `JSONPATHARRAYDEFAULTEMPTY(myJsonRecord, '$.subjects[*].score')`              | `[90, 70]`             |
| `JSONPATHARRAYDEFAULTEMPTY(myJsonRecord, '$.subjects[*].homework_grades[1]')` | `[85, 65]`             |
| `JSONPATHARRAYDEFAULTEMPTY(myJsonRecord, '$.subjects[*].homework_grades[7]')` | `[]`                   |

This function can be used in the [table config](https://docs.pinot.apache.org/release-0.11.0/configuration-reference/table) to extract the `name`, `score`, and second value of `homework_grades` into their respective columns , as described below:

```json
{
   "tableConfig":{
      "ingestionConfig":{
         "transformConfigs":[
            {
               "columnName":"names",
               "transformFunction":"JSONPATHARRAYDEFAULTEMPTY(data, '$.subjects[*].name')"
            },
            {
               "columnName":"ages",
               "transformFunction":"JSONPATHARRAYDEFAULTEMPTY(data, '$.subjects[*].score')"
            },
            {
               "columnName":"homeworkGrades",
               "transformFunction":"JSONPATHARRAYDEFAULTEMPTY(data, '$.subjects[*].homework_grades[1]')"
            }
         ]
      }
   }
}
```


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.pinot.apache.org/release-0.11.0/configuration-reference/functions/jsonpatharraydefaultempty.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.