JSON_EXTRACT returns the sub-JSON document at the specified path, and otherwise, returns NULL.
Syntax
Aliases
Parameters
| Parameter | Description | Supported input types |
|---|---|---|
<json> | The JSON document. | TEXT |
<json_path_expression> | A JSON path that specifies the location of the desired sub-document within the JSON document. | TEXT |
<path_syntax> | The expected syntax of the <json_path_expression>, currently supports only the ‘JSONPointer’ syntax. For more information, see JSON pointer expression syntax. | TEXT |
Return Type
TEXT
- If any input values are
NULL, the function will returnNULL.
Examples
For the JSON document indicated by<json_common_example> below,
see JSON common example. The returned result is based on the following example.
Example
The following code example extracts the value at the path /value/dyid from the JSON document represented by <json_common_example> using the JSONPointer syntax:
dyid is associated with the value 987 within the value object, and the function retrieves and returns this value as a string.
Example
The following code example attempts to extract a value from the path /value/no_such_key in the JSON document represented by <json_common_example>:
NULL because the key no_such_key does not exist.
Example
The following code example extracts the value at the path /value/uid from the JSON document represented by <json_common_example>:
'"987654"' because the value associated with the uid key in the JSON document is the string 987654. The function retrieves this value with double quotes, indicating it’s a JSON string.
Example
The following code example extracts the value at the path /value/keywords from the JSON document represented by <json_common_example>:
["insanely","fast","analytics"] that is associated with the keywords key.
Example
The following code example extracts the third element at index 2 from the array located at the path /value/keywords in the JSON document represented by <json_common_example>:
'"analytics"' because it accesses the third element in the JSON array, which uses zero-based indexing.