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12.17.2 Functions That Create JSON Values

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The functions listed in this section compose JSON values from component elements.

  • JSON_ARRAY([val[, val] ...])

    Evaluates a (possibly empty) list of values and returns a JSON array containing those values.

    1. mysql> SELECT JSON_ARRAY(1, "abc", NULL, TRUE, CURTIME());
    2. +---------------------------------------------+
    3. | JSON_ARRAY(1, "abc", NULL, TRUE, CURTIME()) |
    4. +---------------------------------------------+
    5. | [1, "abc", null, true, "11:30:24.000000"]   |
    6. +---------------------------------------------+

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

    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.

    1. mysql> SELECT JSON_OBJECT('id', 87, 'name', 'carrot');
    2. +-----------------------------------------+
    3. | JSON_OBJECT('id', 87, 'name', 'carrot') |
    4. +-----------------------------------------+
    5. | {"id": 87, "name": "carrot"}            |
    6. +-----------------------------------------+

  • JSON_QUOTE(string)

    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.

    This function is typically used to produce a valid JSON string literal for inclusion within a JSON document.

    Certain special characters are escaped with backslashes per the escape sequences shown in Table 12.22, “JSON_UNQUOTE() Special Character Escape Sequences”.

    1. mysql> SELECT JSON_QUOTE('null'), JSON_QUOTE('"null"');
    2. +--------------------+----------------------+
    3. | JSON_QUOTE('null') | JSON_QUOTE('"null"') |
    4. +--------------------+----------------------+
    5. | "null"             | "\"null\""           |
    6. +--------------------+----------------------+
    7. mysql> SELECT JSON_QUOTE('[1, 2, 3]');
    8. +-------------------------+
    9. | JSON_QUOTE('[1, 2, 3]') |
    10. +-------------------------+
    11. | "[1, 2, 3]"             |
    12. +-------------------------+

You can also obtain JSON values by casting values of other types to the JSON type using CAST(value AS JSON); see Converting between JSON and non-JSON values, for more information.

Two aggregate functions generating JSON values are available. JSON_ARRAYAGG() returns a result set as a single JSON array, and JSON_OBJECTAGG() returns a result set as a single JSON object. For more information, see Section 12.20, “Aggregate (GROUP BY) Functions”.


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Document created the 26/06/2006, last modified the 26/10/2018
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