Accepts a JSON document and pointer expression. If the key exists and holds a JSON object (map), JSON_POINTER_EXTRACT_KEYS returns all the keys in that object as SQL ARRAY(TEXT), removing outer quotes and decoding characters. Otherwise, it returns NULL.

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Syntax

JSON_POINTER_EXTRACT_KEYS
(<json>, <json_pointer_expression>)

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Parameters

ParameterDescriptionSupported input types
<json>The JSON document.TEXT
<json_pointer_expression>A JSON pointer expression to the location of the desired sub-document in the JSON. For more information, see JSON pointer expression syntax.TEXT

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Return Type

ARRAY(TEXT)

  • If any input values are NULL, the function will return NULL.

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Examples

For the JSON document indicated by <json_common_example> below, see JSON common example.

Example

The following code example extracts all the keys at path /value from the JSON document, removes the outermost quotes, and returns the result as SQL ARRAY(TEXT), labeled as res:

SELECT JSON_POINTER_EXTRACT_KEYS(<json_common_example>, '/value') AS res

Returns

The previous code example returns the following:

res (ARRAY(TEXT))

Example

The following code example attempts to extract the keys at the path /value/no_such_key from the JSON document:

SELECT JSON_POINTER_EXTRACT_KEYS(<json_common_example>, '/value/no_such_key') AS res

Returns

The previous code example returns the NULL with the result labeled as res, because the key does not exist:

res (ARRAY(TEXT))
NULL

Example

The following code example attempts to extract the value at the path /value/keywords from the JSON document:

SELECT JSON_POINTER_EXTRACT_KEYS(<json_common_example>,'/value/keywords') AS res

Returns

The previous code example returns NULL, labeled as res because the value at the specified path is an array, not an object:

res (ARRAY(TEXT))
NULL