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官方文档：JSON Functions
| Name | Description |
|---|---|
JSON_APPEND() |
Append data to JSON document |
JSON_ARRAY() |
Create JSON array |
JSON_ARRAY_APPEND() |
Append data to JSON document |
JSON_ARRAY_INSERT() |
Insert into JSON array |
-> |
Return value from JSON column after evaluating path; equivalent to JSON_EXTRACT(). |
JSON_CONTAINS() |
Whether JSON document contains specific object at path |
JSON_CONTAINS_PATH() |
Whether JSON document contains any data at path |
JSON_DEPTH() |
Maximum depth of JSON document |
JSON_EXTRACT() |
Return data from JSON document |
->> |
Return value from JSON column after evaluating path and unquoting the result; equivalent to JSON_UNQUOTE(JSON_EXTRACT()). |
JSON_INSERT() |
Insert data into JSON document |
JSON_KEYS() |
Array of keys from JSON document |
JSON_LENGTH() |
Number of elements in JSON document |
JSON_MERGE() |
Merge JSON documents |
JSON_OBJECT() |
Create JSON object |
JSON_QUOTE() |
Quote JSON document |
JSON_REMOVE() |
Remove data from JSON document |
JSON_REPLACE() |
Replace values in JSON document |
JSON_SEARCH() |
Path to value within JSON document |
JSON_SET() |
Insert data into JSON document |
JSON_TYPE() |
Type of JSON value |
JSON_UNQUOTE() |
Unquote JSON value |
JSON_VALID() |
Whether JSON value is valid |
MySQL里的json分为json array和json object。 $表示整个json对象，在索引数据时用下标(对于json array，从0开始)或键值(对于json object，含有特殊字符的key要用"括起来，比如$."my name")。
例如：[3, {"a": [5, 6], "b": 10}, [99, 100]]，那么：
$[0]：3
$[1]： {"a": [5, 6], "b": 10}
$[2] ：[99, 100]
$[3] ： NULL
$[1].a：[5, 6]
$[1].a[1]：6
$[1].b：10
$[2][0]：99
json中的数据可以用 =, <, <=, >, >=, <>, !=, and <=> 进行比较。但json里的数据类型可以是多样的，那么在不同类型之间进行比较时，就有优先级了，高优先级的要大于低优先级的（可以用JSON_TYPE()函数查看类型）。优先级从高到低如下：
BLOB BIT OPAQUE DATETIME TIME DATE BOOLEAN ARRAY OBJECT STRING INTEGER, DOUBLE NULL
JSON_ARRAY(val1,val2,val3...)
生成一个包含指定元素的json数组。
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(key1,val1,key2,val2...)
生成一个包含指定K-V对的json object。如果有key为NULL或参数个数为奇数，则抛错。
mysql> SELECT JSON_OBJECT(‘id‘, 87, ‘name‘, ‘carrot‘);
+-----------------------------------------+
| JSON_OBJECT(‘id‘, 87, ‘name‘, ‘carrot‘) |
+-----------------------------------------+
| {"id": 87, "name": "carrot"} |
+-----------------------------------------+
3.1.3 JSON_QUOTE
JSON_QUOTE(json_val)
将json_val用"号括起来。
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]" | +-------------------------+
CONVERT(json_string,JSON)
mysql> select CONVERT(‘{"mail": "amy@gmail.com", "name": "Amy"}‘,JSON);
+----------------------------------------------------------+
| CONVERT(‘{"mail": "amy@gmail.com", "name": "Amy"}‘,JSON) |
+----------------------------------------------------------+
| {"mail": "amy@gmail.com", "name": "Amy"} |
+----------------------------------------------------------+
end
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原文地址：http://www.cnblogs.com/waterystone/p/5626098.html
