JSON_ARRAY([val[, val] ...])JSON_ARRAY([val[, val] ...])

评估一个（可能为空的）值列表，并返回一个包含这些值的 JSON 数组。Evaluates a (possibly empty) list of values and returns a JSON array containing those values.

mysql> SELECT JSON_ARRAY(1, "abc", NULL, TRUE, CURTIME());
+---------------------------------------------+
| JSON_ARRAY(1, "abc", NULL, TRUE, CURTIME()) |
+---------------------------------------------+
| [1, "abc", null, true, "11:30:24.000000"]   |
+---------------------------------------------+

JSON_OBJECT([key, val[, key, val] ...])

计算一个（可能为空的）键值对列表，并返回包含这些键值对的 JSON 对象。如果任意键名为 NULL 或参数数量为奇数，会产生错误。Evaluates a (possibly empty) list of key-value pairs and returns a JSON object containing those pairs. An error occurs if any key name is NULL or the number of arguments is odd.

mysql> SELECT JSON_OBJECT('id', 87, 'name', 'carrot');
+-----------------------------------------+
| JSON_OBJECT('id', 87, 'name', 'carrot') |
+-----------------------------------------+
| {"id": 87, "name": "carrot"}            |
+-----------------------------------------+

JSON_QUOTE(string)

通过用双引号字符包裹字符串并转义内部的引号和其他字符，将字符串作为 JSON 值引用，然后将结果作为 utf8mb4 字符串返回。如果参数为 NULL，则返回 NULL。Quotes a string as a JSON value by wrapping it with double quote characters and escaping interior quote and other characters, then returning the result as a utf8mb4 string. Returns NULL if the argument is NULL.

此函数通常用于生成一个有效的 JSON 字符串字面值，以便包含在 JSON 文档中。This function is typically used to produce a valid JSON string literal for inclusion within a JSON document.

根据表 14.23，“JSON_UNQUOTE() 特殊字符转义序列”中显示的转义序列，一些特殊字符使用反斜杠进行转义。Certain special characters are escaped with backslashes per the escape sequences shown in Table 14.23, “JSON_UNQUOTE() Special Character Escape Sequences”.

mysql> SELECT JSON_QUOTE('null'), JSON_QUOTE('"null"');
+--------------------+----------------------+
| JSON_QUOTE('null') | JSON_QUOTE('"null"') |
+--------------------+----------------------+
| "null"             | "\"null\""           |
+--------------------+----------------------+
mysql> SELECT JSON_QUOTE('[1, 2, 3]');
+-------------------------+
| JSON_QUOTE('[1, 2, 3]') |
+-------------------------+
| "[1, 2, 3]"             |
+-------------------------+