JSON_EXTRACT_PATH_TEXT

path_name によって Json 文字列から値を抽出します。値は String として返されます。いずれかの引数が NULL の場合は NULL を返します。この関数は to_varchar(GET_PATH(PARSE_JSON(JSON), PATH_NAME)) と同等です。

構文

JSON_EXTRACT_PATH_TEXT( <expr>, <path_name> )

引数

戻り値の型

String

例

SELECT json_extract_path_text('{"k1":[0,1,2], "k2":{"k3":3,"k4":4}}', 'k1[0]');
+-------------------------------------------------------------------------+
| json_extract_path_text('{"k1":[0,1,2], "k2":{"k3":3,"k4":4}}', 'k1[0]') |
+-------------------------------------------------------------------------+
| 0                                                                       |
+-------------------------------------------------------------------------+

SELECT json_extract_path_text('{"k1":[0,1,2], "k2":{"k3":3,"k4":4}}', 'k2:k3');
+-------------------------------------------------------------------------+
| json_extract_path_text('{"k1":[0,1,2], "k2":{"k3":3,"k4":4}}', 'k2:k3') |
+-------------------------------------------------------------------------+
| 3                                                                       |
+-------------------------------------------------------------------------+

SELECT json_extract_path_text('{"k1":[0,1,2], "k2":{"k3":3,"k4":4}}', 'k2.k4');
+-------------------------------------------------------------------------+
| json_extract_path_text('{"k1":[0,1,2], "k2":{"k3":3,"k4":4}}', 'k2.k4') |
+-------------------------------------------------------------------------+
| 4                                                                       |
+-------------------------------------------------------------------------+

SELECT json_extract_path_text('{"k1":[0,1,2], "k2":{"k3":3,"k4":4}}', 'k2.k5');
+-------------------------------------------------------------------------+
| json_extract_path_text('{"k1":[0,1,2], "k2":{"k3":3,"k4":4}}', 'k2.k5') |
+-------------------------------------------------------------------------+
| NULL                                                                    |
+-------------------------------------------------------------------------+