JSONPATHARRAYDEFAULTEMPTY
This section contains reference documentation for the JSONPATHARRAYDEFAULTEMPTY function.
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.JSONPATHARRAYDEFAULTEMPTY(jsonField, 'jsonPath')
Arguments | Description |
|---|---|
jsonField | An Identifier/Expression contains JSON documents. |
'jsonPath' |
'jsonPath'` is a literal. Pinot uses single quotes to distinguish them from identifiers.
You can use the Jayway JsonPath Evaluator Tool to test JSON expressions before you import any data.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 |
|---|---|
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 to extract the
name, score, and second value of homework_grades into their respective columns , as described below:{
"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]')"
}
]
}
}
}
Last modified 1yr ago