get_json_double

description

Syntax

`DOUBLE get_json_double(VARCHAR json_str, VARCHAR json_path)

Parse and get the floating-point content of the specified path in the JSON string. Where json_path must start with the $symbol and use. as the path splitter. If the path contains…, double quotation marks can be used to surround it. Use [] to denote array subscripts, starting at 0. The content of path cannot contain “,[and]. If the json_string format is incorrect, or the json_path format is incorrect, or matches cannot be found, NULL is returned.

example

  1. Get the value of key as “k1”
  1. mysql > SELECT get'u json 'double ('{"k1":1.3, "k2":"2"}, "$.k1");
  2. +-------------------------------------------------+
  3. Get double ('{"k1":1.3, "k2":"2"},'$.k1')'124get;
  4. +-------------------------------------------------+
  5. |                                             1.3 |
  6. +-------------------------------------------------+
  1. Get the second element of the array whose key is “my. key”
  1. mysql > SELECT get'u json 'double ('{"k1":"v1", "my.key":[1.1, 2.2, 3.3]}','$"my.key"[1]);
  2. +---------------------------------------------------------------------------+
  3. Get me a double ('{"k1":"v1", "my.key":[1.1, 2.2, 3.3]}','$"my.key"[1]])'124;
  4. +---------------------------------------------------------------------------+
  5. |                                                                       2.2 |
  6. +---------------------------------------------------------------------------+
  1. Get the first element in an array whose secondary path is k1. key - > K2
  1. mysql > SELECT get'u json 'double ('{"k1.key":{"k2":[1.1, 2.2]}}','$."k1.key".k2 [0]);
  2. +---------------------------------------------------------------------+
  3. Get double ('{"k1.key":{"k2":[1.1, 2.2]}}','$"k1.key.k2 [0]])'124;
  4. +---------------------------------------------------------------------+
  5. |                                                                 1.1 |
  6. +---------------------------------------------------------------------+

keyword GET_JSON_DOUBLE,GET,JSON,DOUBLE