JSON_EXTRACT - MaxCompute - Alibaba Cloud Documentation Center

Parses the data that matches a JSON path in a JSON expression. If the JSON path that you specify is invalid, an error is reported.

Syntax

json json_extract(<json>, <json_path>)

Parameters

json: required. This parameter specifies the JSON expression that you want to process.
json_path: required. This parameter specifies the JSON path of the value that you want to be returned.

Return value

The return value is of the JSON type.

Examples

Example 1: Obtain the value of the key a from a JSON object.
```
select json_extract(json '{"a":1, "b":2}', '$.a');
```
The following result is returned:
```
+-----+
| _c0 |
+-----+
| 1   |
+-----+
```
Example 2: NULL is returned if the specified key does not exist in the JSON object.
```
select json_extract(json '{"a":1, "b":2}', 'strict $.c');
```
The following result is returned:
```
+-----+
| _c0 |
+-----+
| NULL |
+-----+
```
Example 3: The error message Invalid argument - Param json path $invalid_json_path is invalid is returned if the JSON path that you specified is invalid.
```
select json_extract(json '{"a":1, "b":2}', '$a');
```
The following result is returned:
```
-- An error message is returned.
Invalid argument - Param json path $invalid_json_path is invalid
```

Related functions

JSON_EXTRACT is a complex type function. For more information about the functions that are used to process data of complex data types, such as ARRAY, MAP, STRUCT, and JSON, see Complex type functions.