jsonpathstring.md

description
This section contains reference documentation for the JSONPATHSTRING function.

JSONPATHSTRING

Extracts the String value from jsonField based on 'jsonPath', use optional defaultValuefor null or parsing error. This function can only be used in an ingestion transformation function.

Signature

JSONPATHSTRING(jsonField, 'jsonPath', [defaultValue])

Arguments	Description
jsonField	An Identifier/Expression contains JSON documents.
'jsonPath'	Follows JsonPath Syntax to read values from JSON documents.

{% hint style="warning" %} 'jsonPath'` is a literal. Pinot uses single quotes to distinguish them from identifiers. {% endhint %}

Usage Examples

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

{
  "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
JSONPATHSTRING(data, '$.age')	"24"

This function can be used in the table config to extract the age property into the age column, as described below:

{
   "tableConfig":{
      "ingestionConfig":{
         "transformConfigs":[
            {
               "columnName":"age",
               "transformFunction":"JSONPATHSTRING(data, '$.age')"
            }
         ]
      }
   }
}