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JSONExtract Function

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JSONExtract Function

DescriptionPick out one or more portions of a JSON input string as a single value, an array of values, a JSON object, or list of items, via a standard JSONPath expression.
RemarkTakes two arguments:
  • JSONtoParse: The input JSON to parse and return the value(s) from
  • JSONPath: A JSONPath expression that describes what value(s) to return from JSONtoParse

By default, JSONExtract is done in-memory unless the system administrator explicitly sets a hidden system configuration flag to translate JSONExtract to SQL for processing in the Data Source. JSONPath is a standardized format for accessing elements of a JSON structure.

Examples
"JSONtoParse ="{
   "products":[
      {
         "name":"Côte de Blaye",
         "price":263.50
      },
      {
         "name":"Ipoh Coffee",
         "price":46.0
      },
      {
         "name":"Vegie-spread",
         "price":43.9
      },
      {
         "name":"Northwoods Cranberry Sauce",
         "price":40
      }
   ]
}

JSONExtract(JSONtoParse, "$..price") returns [263.5,46.0,43.9,40]
JSONExtract(JSONtoParse, "$..products[3].name")returns [“Northwoods Cranberry Sauce”]

JSONtoParse = {"color": "green", "code": "123"}

JSONExtract(JSONtoParse, "$.color") returns green
JSONExtract(JSONtoParse, "$.code") returns 123

JSONExtract in the Data Source

By default, the application will extract JSON in-memory. The system administrator can enable JSON extraction in the database, for those Data Sources that support it, by changing a system configuration setting. Each Data Source implements this function differently, so care should be taken when enabling this feature.

Table A below lists the supported JSONPath expressions for in-memory processing and processing in the supported Data Source types.

Table A — Supported JSONPath Expressions in Data Sources
JSONPath FeatureIn-MemoryMySQLOracleSQL Server 2016+
$YesYesNoNo
$.propYesYesYesYes
$.prop[0]YesYesYesYes
$[1,2]YesNoNoNo
$..recursiveYesNoNoNo
$.prop.*YesYesNoNo
$[*]YesYesNoNo
$[3:5]YesNoNoNo
$[6:]YesNoNoNo
$[:3]YesNoNoNo
$[-2:]YesNoNoNo
$[?(@.prop == val)]NoNoNoNo
$[?(@.prop != val)]NoNoNoNo
$[?(@.prop > val)]NoNoNoNo
$[?(@.prop < val)]NoNoNoNo
$[?(@.prop >= val)]NoNoNoNo
$[?(@.prop <= val)]NoNoNoNo
$[?(@.prop =~ val)]NoNoNoNo
$[?(!@.prop =~ val)]NoNoNoNo
$[?(@.prop == val && @.prop == val)]NoNoNoNo
$[?(@.prop == val || @.prop == val)]NoNoNoNo
$[?(@.prop in ['1', '2', '3'])]NoNoNoNo
$[?(@.prop nin ['1', '2', '3'])]NoNoNoNo

Notes and Exceptions

  • IBM DB2 — testing has shown this data source does not support JSONExtract although its documentation says that it does
  • PostgreSQL — no support for JSONPath syntax, so JSONExtract can only be done in-memory
  • Oracle — if the JSONPath expression selects a JSON object from within the main JSON object, the return value will be null

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