背景:MySQL 5.7.13 + 支持josn
本章先是JSON的查找操作,后半部分为JSON更新查找;
接下来开始熟悉5.7.13版本后带来的相关函数操作或者特性,本文章所包含的范围没有涉及到json的索引,有兴趣的小伙伴可以分享下哦。
1、JSON_CONTAINS(target, candidate[, path])
表示从target的路径path搜索candidate,如果j不存在path直接null,存在的话直接匹配,有为1,没有为0.
如果$后面没有跟具体的元素,
如'$'则表示当前json;使用'$[0]'则获取数组json的第一个元素,'$[*]'获取全部数组;
目前支持的形式有'$'、'$[N or *]'、'$[N or *][N or *].key'、'$**'(这个匹配所有路径)
示例:
mysql> SET @j = '{"a": 1, "b": 2, "c": {"d": 4}}';
mysql> SET @j2 = '1';
mysql> SELECT JSON_CONTAINS(@j, @j2, '$.a');
+-------------------------------+
| JSON_CONTAINS(@j, @j2, '$.a') |
+-------------------------------+
| 1 |
+-------------------------------+
mysql> SELECT JSON_CONTAINS(@j, @j2, '$.b');
+-------------------------------+
| JSON_CONTAINS(@j, @j2, '$.b') |
+-------------------------------+
| 0 |
+-------------------------------+
2、JSON_CONTAINS_PATH(json_doc, one_or_all, path[, path] …)
one表示后面的路径有一个或多个存在就返回1,否则为0;
all表示后面的路径都必须存在就返回1,否则就0;
示例:
mysql> SET @j = '{"a": 1, "b": 2, "c": {"d": 4}}';
mysql> SELECT JSON_CONTAINS_PATH(@j, 'one', '$.a', '$.e');
+---------------------------------------------+
| JSON_CONTAINS_PATH(@j, 'one', '$.a', '$.e') |
+---------------------------------------------+
| 1 |
+---------------------------------------------+
mysql> SELECT JSON_CONTAINS_PATH(@j, 'all', '$.a', '$.e');
+---------------------------------------------+
| JSON_CONTAINS_PATH(@j, 'all', '$.a', '$.e') |
+---------------------------------------------+
| 0 |
+---------------------------------------------+
3、JSON_EXTRACT(json_doc, path[, path] …)
EXTRACT表示从json_doc提取一个或多个path的值。
示例:
mysql> SELECT JSON_EXTRACT('[10, 20, [30, 40]]', '$[1]');
+--------------------------------------------+
| JSON_EXTRACT('[10, 20, [30, 40]]', '$[1]') |
+--------------------------------------------+
| 20 |
+--------------------------------------------+
mysql> SELECT JSON_EXTRACT('[10, 20, [30, 40]]', '$[1]', '$[0]');
+----------------------------------------------------+
| JSON_EXTRACT('[10, 20, [30, 40]]', '$[1]', '$[0]') |
+----------------------------------------------------+
| [20, 10] |
+----------------------------------------------------+
创建一个带有JSON字段的表:
mysql> CREATE TABLE tj10 (a JSON, b INT);
Query OK, 0 rows affected (0.26 sec)
mysql> INSERT INTO tj10
> VALUES ("[3,10,5,17,44]", 33), ("[3,10,5,17,[22,44,66]]", 0);
Query OK, 1 row affected (0.04 sec)
mysql> SELECT a->"$[4]" FROM tj10;
+--------------+
| a->"$[4]" |
+--------------+
| 44 |
| [22, 44, 66] |
+--------------+
2 rows in set (0.00 sec)
4、column->path
除了JSON_EXTRACT这个可以提取JSON里某个属性,也可以采用column->path这种形式,可以说它们是等价的。
示例:
mysql> SELECT c, JSON_EXTRACT(c, "$.id"), g
> FROM jemp
> WHERE JSON_EXTRACT(c, "$.id") > 1
> ORDER BY JSON_EXTRACT(c, "$.name");
+-------------------------------+-----------+------+
| c | c->"$.id" | g |
+-------------------------------+-----------+------+
| {"id": "3", "name": "Barney"} | "3" | 3 |
| {"id": "4", "name": "Betty"} | "4" | 4 |
| {"id": "2", "name": "Wilma"} | "2" | 2 |
+-------------------------------+-----------+------+
3 rows in set (0.00 sec)
mysql> SELECT c, c->"$.id", g
> FROM jemp
> WHERE c->"$.id" > 1
> ORDER BY c->"$.name";
+-------------------------------+-----------+------+
| c | c->"$.id" | g |
+-------------------------------+-----------+------+
| {"id": "3", "name": "Barney"} | "3" | 3 |
| {"id": "4", "name": "Betty"} | "4" | 4 |
| {"id": "2", "name": "Wilma"} | "2" | 2 |
5、column->>path
在使用column->path 这种形式获取的元素是带有双引号的,现在有两种方式去除这种引号,如column->>path 或者 JSON_UNQUOTE(column->path)。
示例:
mysql> SELECT * FROM jemp WHERE g > 2;
+-------------------------------+------+
| c | g |
+-------------------------------+------+
| {"id": "3", "name": "Barney"} | 3 |
| {"id": "4", "name": "Betty"} | 4 |
+-------------------------------+------+
2 rows in set (0.01 sec)
mysql> SELECT c->'$.name' AS name
-> FROM jemp WHERE g > 2;
+----------+
| name |
+----------+
| "Barney" |
| "Betty" |
+----------+
2 rows in set (0.00 sec)
mysql> SELECT JSON_UNQUOTE(c->'$.name') AS name
-> FROM jemp WHERE g > 2;
+--------+
| name |
+--------+
| Barney |
| Betty |
+--------+
2 rows in set (0.00 sec)
mysql> SELECT c->>'$.name' AS name
-> FROM jemp WHERE g > 2;
+--------+
| name |
+--------+
| Barney |
| Betty |
+--------+
6、JSON_KEYS(json_doc[, path])
返回JSON的key,如果指定了path,不存在则返回null,存在就返回顶级key。
示例:
mysql> SELECT JSON_KEYS('{"a": 1, "b": {"c": 30}}');
+---------------------------------------+
| JSON_KEYS('{"a": 1, "b": {"c": 30}}') |
+---------------------------------------+
| ["a", "b"] |
+---------------------------------------+
mysql> SELECT JSON_KEYS('{"a": 1, "b": {"c": 30}}', '$.b');
+----------------------------------------------+
| JSON_KEYS('{"a": 1, "b": {"c": 30}}', '$.b') |
+----------------------------------------------+
| ["c"] |
+----------------------------------------------+
7、JSON_SEARCH(json_doc, one_or_all, search_str[, escape_char[, path] …])
One 表示查到第一个匹配到search_str的元素下标,all返回所有元素下标,这里的下标是指:数组则是下标,map则是key;
如果没有匹配到则返回null;search_str 使用% 进行模糊查询;escape_char表示不需要查询的字符串,如果需要使用到path且跳过该escape_char则使用null表示跳过,如果没有提供search_str参数则返回null;
示例:
mysql> SET @j = '["abc", [{"k": "10"}, "def"], {"x":"abc"}, {"y":"bcd"}]';
mysql> SELECT JSON_SEARCH(@j, 'one', 'abc');
+-------------------------------+
| JSON_SEARCH(@j, 'one', 'abc') |
+-------------------------------+
| "$[0]" |
+-------------------------------+
mysql> SELECT JSON_SEARCH(@j, 'all', 'abc');
+-------------------------------+
| JSON_SEARCH(@j, 'all', 'abc') |
+-------------------------------+
| ["$[0]", "$[2].x"] |
+-------------------------------+
mysql> SELECT JSON_SEARCH(@j, 'all', 'ghi');
+-------------------------------+
| JSON_SEARCH(@j, 'all', 'ghi') |
+-------------------------------+
| NULL |
+-------------------------------+
mysql> SELECT JSON_SEARCH(@j, 'all', '10');
+------------------------------+
| JSON_SEARCH(@j, 'all', '10') |
+------------------------------+
| "$[1][0].k" |
+------------------------------+
mysql> SELECT JSON_SEARCH(@j, 'all', '10', NULL, '$');
+-----------------------------------------+
| JSON_SEARCH(@j, 'all', '10', NULL, '$') |
+-----------------------------------------+
| "$[1][0].k" |
+-----------------------------------------+
mysql> SELECT JSON_SEARCH(@j, 'all', '10', NULL, '$[*]');
+--------------------------------------------+
| JSON_SEARCH(@j, 'all', '10', NULL, '$[*]') |
+--------------------------------------------+
| "$[1][0].k" |
+--------------------------------------------+
mysql> SELECT JSON_SEARCH(@j, 'all', '10', NULL, '$**.k');
+---------------------------------------------+
| JSON_SEARCH(@j, 'all', '10', NULL, '$**.k') |
+---------------------------------------------+
| "$[1][0].k" |
+---------------------------------------------+
mysql> SELECT JSON_SEARCH(@j, 'all', '10', NULL, '$[*][0].k');
+-------------------------------------------------+
| JSON_SEARCH(@j, 'all', '10', NULL, '$[*][0].k') |
+-------------------------------------------------+
| "$[1][0].k" |
+-------------------------------------------------+
mysql> SELECT JSON_SEARCH(@j, 'all', '10', NULL, '$[1]');
+--------------------------------------------+
| JSON_SEARCH(@j, 'all', '10', NULL, '$[1]') |
+--------------------------------------------+
| "$[1][0].k" |
+--------------------------------------------+
mysql> SELECT JSON_SEARCH(@j, 'all', '10', NULL, '$[1][0]');
+-----------------------------------------------+
| JSON_SEARCH(@j, 'all', '10', NULL, '$[1][0]') |
+-----------------------------------------------+
| "$[1][0].k" |
+-----------------------------------------------+
mysql> SELECT JSON_SEARCH(@j, 'all', 'abc', NULL, '$[2]');
+---------------------------------------------+
| JSON_SEARCH(@j, 'all', 'abc', NULL, '$[2]') |
+---------------------------------------------+
| "$[2].x" |
+---------------------------------------------+
mysql> SELECT JSON_SEARCH(@j, 'all', '%a%');
+-------------------------------+
| JSON_SEARCH(@j, 'all', '%a%') |
+-------------------------------+
| ["$[0]", "$[2].x"] |
+-------------------------------+
mysql> SELECT JSON_SEARCH(@j, 'all', '%b%');
+-------------------------------+
| JSON_SEARCH(@j, 'all', '%b%') |
+-------------------------------+
| ["$[0]", "$[2].x", "$[3].y"] |
+-------------------------------+
mysql> SELECT JSON_SEARCH(@j, 'all', '%b%', NULL, '$[0]');
+---------------------------------------------+
| JSON_SEARCH(@j, 'all', '%b%', NULL, '$[0]') |
+---------------------------------------------+
| "$[0]" |
+---------------------------------------------+
mysql> SELECT JSON_SEARCH(@j, 'all', '%b%', NULL, '$[2]');
+---------------------------------------------+
| JSON_SEARCH(@j, 'all', '%b%', NULL, '$[2]') |
+---------------------------------------------+
| "$[2].x" |
+---------------------------------------------+
mysql> SELECT JSON_SEARCH(@j, 'all', '%b%', NULL, '$[1]');
+---------------------------------------------+
| JSON_SEARCH(@j, 'all', '%b%', NULL, '$[1]') |
+---------------------------------------------+
| NULL |
+---------------------------------------------+
mysql> SELECT JSON_SEARCH(@j, 'all', '%b%', '', '$[1]');
+-------------------------------------------+
| JSON_SEARCH(@j, 'all', '%b%', '', '$[1]') |
+-------------------------------------------+
| NULL |
+-------------------------------------------+
mysql> SELECT JSON_SEARCH(@j, 'all', '%b%', '', '$[3]');
+-------------------------------------------+
| JSON_SEARCH(@j, 'all', '%b%', '', '$[3]') |
+-------------------------------------------+
| "$[3].y" |
+-------------------------------------------+
接下来是关于JSON的更新查找
以下大部分操作需要校验path的合法性,否则会出现错误。
https://dev.mysql.com/doc/refman/5.7/en/json-modification-functions.html
1、JSON_ARRAY_APPEND(json_doc, path, val[, path, val] …)
若path是指向整个json那就插入该JSON的最后的位置,
若是带有路径形式则插入指定的下标及在该下标的元素添加后缀。
可以path,val形式进行相连添加
示例:
mysql> SET @j = '["a", ["b", "c"], "d"]';
mysql> SELECT JSON_ARRAY_APPEND(@j, '$[1]', 1);
+----------------------------------+
| JSON_ARRAY_APPEND(@j, '$[1]', 1) |
+----------------------------------+
| ["a", ["b", "c", 1], "d"] |
+----------------------------------+
mysql> SET @j = '{"a": 1, "b": [2, 3], "c": 4}';
mysql> SELECT JSON_ARRAY_APPEND(@j, '$.b', 'x');
+------------------------------------+
| JSON_ARRAY_APPEND(@j, '$.b', 'x') |
+------------------------------------+
| {"a": 1, "b": [2, 3, "x"], "c": 4} |
+------------------------------------+
mysql> SET @j = '{"a": 1}';
mysql> SELECT JSON_ARRAY_APPEND(@j, '$', 'z');
+---------------------------------+
| JSON_ARRAY_APPEND(@j, '$', 'z') |
+---------------------------------+
| [{"a": 1}, "z"] |
+---------------------------------+
2、JSON_ARRAY_INSERT(json_doc, path, val[, path, val] …)
首先会校验json_doc是否是JSON,若任何参数为Null则返回null;
在指定的路径插入值,往后的路径向后移;如果有多个path,val 则先执行前面的生成一个新的json后面的匹配path将不执行;
示例:
mysql> SET @j = '["a", {"b": [1, 2]}, [3, 4]]';
mysql> SELECT JSON_ARRAY_INSERT(@j, '$[1]', 'x');
+------------------------------------+
| JSON_ARRAY_INSERT(@j, '$[1]', 'x') |
+------------------------------------+
| ["a", "x", {"b": [1, 2]}, [3, 4]] |
+------------------------------------+
mysql> SELECT JSON_ARRAY_INSERT(@j, '$[1].b[0]', 'x');
+-----------------------------------------+
| JSON_ARRAY_INSERT(@j, '$[1].b[0]', 'x') |
+-----------------------------------------+
| ["a", {"b": ["x", 1, 2]}, [3, 4]] |
+-----------------------------------------+
3、JSON_INSERT(json_doc, path, val[, path, val] …)
属性检验json_doc合法性;如果json_doc的path存在,则不会覆盖现有的值,
不存在的话就加入path-value,返回的是json_doc + path-val,原来的JSON不会变化
示例:
mysql> SET @j = '{ "a": 1, "b": [2, 3]}';
mysql> SELECT JSON_INSERT(@j, '$.a', 10, '$.c', '[true, false]');
+----------------------------------------------------+
| JSON_INSERT(@j, '$.a', 10, '$.c', '[true, false]') |
+----------------------------------------------------+
| {"a": 1, "b": [2, 3], "c": "[true, false]"} |
+----------------------------------------------------+
mysql> SELECT JSON_INSERT(@j, '$.a', 10, '$.c', CAST('[true, false]' AS JSON));
+------------------------------------------------------------------+
| JSON_INSERT(@j, '$.a', 10, '$.c', CAST('[true, false]' AS JSON)) |
+------------------------------------------------------------------+
| {"a": 1, "b": [2, 3], "c": [true, false]} |
+------------------------------------------------------------------+
1 row in set (0.00 sec)
4、JSON_MERGE(json_doc, json_doc[, json_doc] …)
若参数为Null则返回Null,合并多个JSON,也会校验这些JSON。
示例:
mysql> SELECT JSON_MERGE('[1, 2]', '[true, false]');
+---------------------------------------+
| JSON_MERGE('[1, 2]', '[true, false]') |
+---------------------------------------+
| [1, 2, true, false] |
+---------------------------------------+
mysql> SELECT JSON_MERGE('{"name": "x"}', '{"id": 47}');
+-------------------------------------------+
| JSON_MERGE('{"name": "x"}', '{"id": 47}') |
+-------------------------------------------+
| {"id": 47, "name": "x"} |
+-------------------------------------------+
mysql> SELECT JSON_MERGE('[1, 2]', '{"id": 47}');
+------------------------------------+
| JSON_MERGE('[1, 2]', '{"id": 47}') |
+------------------------------------+
| [1, 2, {"id": 47}] |
+------------------------------------+
5、JSON_REMOVE(json_doc, path[, path] …)
参数不能为Null,且校验JSON;指定多个path,前面的先执行后变化的json_doc在执行后面一个path;
示例:
mysql> SET @j = '["a", ["b", "c"], "d"]';
mysql> SELECT JSON_REMOVE(@j, '$[1]');
+-------------------------+
| JSON_REMOVE(@j, '$[1]') |
+-------------------------+
| ["a", "d"] |
+-------------------------+
6、JSON_REPLACE(json_doc, path, val[, path, val] …)
参数不能为Null,且JSON合法,path存在则覆盖,不存在就不操作;
示例:
mysql> SET @j = '{ "a": 1, "b": [2, 3]}';
mysql> SELECT JSON_REPLACE(@j, '$.a', 10, '$.c', '[true, false]');
+-----------------------------------------------------+
| JSON_REPLACE(@j, '$.a', 10, '$.c', '[true, false]') |
+-----------------------------------------------------+
| {"a": 10, "b": [2, 3]} |
+-----------------------------------------------------+
7、JSON_SET(json_doc, path, val[, path, val] …)
参数不能为Null,且JSON合法,若path存在则覆盖,不存在则新增元素;
示例:
mysql> SET @j = '{ "a": 1, "b": [2, 3]}';
mysql> SELECT JSON_SET(@j, '$.a', 10, '$.c', '[true, false]');
+-------------------------------------------------+
| JSON_SET(@j, '$.a', 10, '$.c', '[true, false]') |
+-------------------------------------------------+
| {"a": 10, "b": [2, 3], "c": "[true, false]"} |
+-------------------------------------------------+
mysql> SELECT JSON_INSERT(@j, '$.a', 10, '$.c', '[true, false]');
+----------------------------------------------------+
| JSON_INSERT(@j, '$.a', 10, '$.c', '[true, false]') |
+----------------------------------------------------+
| {"a": 1, "b": [2, 3], "c": "[true, false]"} |
+----------------------------------------------------+
mysql> SELECT JSON_REPLACE(@j, '$.a', 10, '$.c', '[true, false]');
+-----------------------------------------------------+
| JSON_REPLACE(@j, '$.a', 10, '$.c', '[true, false]') |
+-----------------------------------------------------+
| {"a": 10, "b": [2, 3]} |
+-----------------------------------------------------+
8、JSON_UNQUOTE(json_val)
去除引用字符双引号,及配合@@sql_mode = 'NO_BACKSLASH_ESCAPES'开启或禁用 转义字符
示例:
mysql> SET @j = '"abc"';
mysql> SELECT @j, JSON_UNQUOTE(@j);
+-------+------------------+
| @j | JSON_UNQUOTE(@j) |
+-------+------------------+
| "abc" | abc |
+-------+------------------+
现在对转义字符操作;
示例:
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