get_json_double

Description

This function analyzes and gets the floating point value from a specified path in json string. json_path must start with $ and use . as the path separator.

If the path includes ., it could be circled by " and ".

[ ] is used as the array subscripts which start from 0.

Content in the path should not contain " , [ and ].

If the format of json_string or json_path is wrong, this function will return NULL.

Syntax

DOUBLE get_json_double(VARCHAR json_str, VARCHAR json_path)

Examples

1. Get the value whose key is "k1"

   MySQL > SELECT get_json_double('{"k1":1.3, "k2":"2"}', "$.k1");
   +-------------------------------------------------+
   | get_json_double('{"k1":1.3, "k2":"2"}', '$.k1') |
   +-------------------------------------------------+
   |                                             1.3 |
   +-------------------------------------------------+

2. Get the second element in the array whose key is "my.key"

   MySQL > SELECT get_json_double('{"k1":"v1", "my.key":[1.1, 2.2, 3.3]}', '$."my.key"[1]');
   +---------------------------------------------------------------------------+
   | get_json_double('{"k1":"v1", "my.key":[1.1, 2.2, 3.3]}', '$."my.key"[1]') |
   +---------------------------------------------------------------------------+
   |                                                                       2.2 |
   +---------------------------------------------------------------------------+

3. Get the first element in the array whose path is k1.key -> k2.

   MySQL > SELECT get_json_double('{"k1.key":{"k2":[1.1, 2.2]}}', '$."k1.key".k2[0]');
   +---------------------------------------------------------------------+
   | get_json_double('{"k1.key":{"k2":[1.1, 2.2]}}', '$."k1.key".k2[0]') |
   +---------------------------------------------------------------------+
   |                                                                 1.1 |
   +---------------------------------------------------------------------+

keyword

GET_JSON_DOUBLE,GET,JSON,DOUBLE