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SinceVersion 1.2.0
注意：在1.2.x版本中，JSON类型的名字是JSONB，为了尽量跟MySQL兼容，从2.0.0版本开始改名为JSON，老的表仍然可以使用。
description
JSON类型二进制JSON类型，采用二进制JSON格式存储，通过json函数访问JSON内部字段。默认支持1048576 字节（1M），可调大到 2147483643 字节（2G），可通过be配置`jsonb_type_length_soft_limit_bytes`调整
note
与普通STRING类型存储的JSON字符串相比，JSON类型有两点优势1. 数据写入时进行JSON格式校验2. 二进制存储格式更加高效，通过json_extract等函数可以高效访问JSON内部字段，比get_json_xx函数快几倍
example
用一个从建表、导数据、查询全周期的例子说明JSON数据类型的功能和用法。
创建库表
CREATE DATABASE testdb;USE testdb;CREATE TABLE test_json (id INT,j JSON)DUPLICATE KEY(id)DISTRIBUTED BY HASH(id) BUCKETS 10PROPERTIES("replication_num" = "1");
导入数据
stream load 导入test_json.csv测试数据
- 测试数据有2列，第一列id，第二列是json
- 测试数据有25行，其中前18行的json是合法的，后7行的json是非法的
1 \N2 null3 true4 false5 1006 100007 10000000008 11529215046068469769 6.1810 "abcd"11 {}12 {"k1":"v31", "k2": 300}13 []14 [123, 456]15 ["abc", "def"]16 [null, true, false, 100, 6.18, "abc"]17 [{"k1":"v41", "k2": 400}, 1, "a", 3.14]18 {"k1":"v31", "k2": 300, "a1": [{"k1":"v41", "k2": 400}, 1, "a", 3.14]}19 ''20 'abc'21 abc22 100x23 6.a824 {x25 [123, abc]
- 由于有28%的非法数据，默认会失败报错 “too many filtered rows”
curl --location-trusted -u root: -T test_json.csv http://127.0.0.1:8840/api/testdb/test_json/_stream_load{"TxnId": 12019,"Label": "744d9821-9c9f-43dc-bf3b-7ab048f14e32","TwoPhaseCommit": "false","Status": "Fail","Message": "too many filtered rows","NumberTotalRows": 25,"NumberLoadedRows": 18,"NumberFilteredRows": 7,"NumberUnselectedRows": 0,"LoadBytes": 380,"LoadTimeMs": 48,"BeginTxnTimeMs": 0,"StreamLoadPutTimeMs": 1,"ReadDataTimeMs": 0,"WriteDataTimeMs": 45,"CommitAndPublishTimeMs": 0,"ErrorURL": "http://172.21.0.5:8840/api/_load_error_log?file=__shard_2/error_log_insert_stmt_95435c4bf5f156df-426735082a9296af_95435c4bf5f156df_426735082a9296af"}
- 设置容错率参数 ‘max_filter_ratio: 0.3’
curl --location-trusted -u root: -H 'max_filter_ratio: 0.3' -T test_json.csv http://127.0.0.1:8840/api/testdb/test_json/_stream_load{"TxnId": 12017,"Label": "f37a50c1-43e9-4f4e-a159-a3db6abe2579","TwoPhaseCommit": "false","Status": "Success","Message": "OK","NumberTotalRows": 25,"NumberLoadedRows": 18,"NumberFilteredRows": 7,"NumberUnselectedRows": 0,"LoadBytes": 380,"LoadTimeMs": 68,"BeginTxnTimeMs": 0,"StreamLoadPutTimeMs": 2,"ReadDataTimeMs": 0,"WriteDataTimeMs": 45,"CommitAndPublishTimeMs": 19,"ErrorURL": "http://172.21.0.5:8840/api/_load_error_log?file=__shard_0/error_log_insert_stmt_a1463f98a7b15caf-c79399b920f5bfa3_a1463f98a7b15caf_c79399b920f5bfa3"}
- 查看stream load导入的数据，JSON类型的列j会自动转成JSON string展示
mysql> SELECT * FROM test_json ORDER BY id;+------+---------------------------------------------------------------+| id | j |+------+---------------------------------------------------------------+| 1 | NULL || 2 | null || 3 | true || 4 | false || 5 | 100 || 6 | 10000 || 7 | 1000000000 || 8 | 1152921504606846976 || 9 | 6.18 || 10 | "abcd" || 11 | {} || 12 | {"k1":"v31","k2":300} || 13 | [] || 14 | [123,456] || 15 | ["abc","def"] || 16 | [null,true,false,100,6.18,"abc"] || 17 | [{"k1":"v41","k2":400},1,"a",3.14] || 18 | {"k1":"v31","k2":300,"a1":[{"k1":"v41","k2":400},1,"a",3.14]} |+------+---------------------------------------------------------------+18 rows in set (0.03 sec)
insert into 插入数据
- insert 1条数据，总数据从18条增加到19条
mysql> INSERT INTO test_json VALUES(26, '{"k1":"v1", "k2": 200}');Query OK, 1 row affected (0.09 sec){'label':'insert_4ece6769d1b42fd_ac9f25b3b8f3dc02', 'status':'VISIBLE', 'txnId':'12016'}mysql> SELECT * FROM test_json ORDER BY id;+------+---------------------------------------------------------------+| id | j |+------+---------------------------------------------------------------+| 1 | NULL || 2 | null || 3 | true || 4 | false || 5 | 100 || 6 | 10000 || 7 | 1000000000 || 8 | 1152921504606846976 || 9 | 6.18 || 10 | "abcd" || 11 | {} || 12 | {"k1":"v31","k2":300} || 13 | [] || 14 | [123,456] || 15 | ["abc","def"] || 16 | [null,true,false,100,6.18,"abc"] || 17 | [{"k1":"v41","k2":400},1,"a",3.14] || 18 | {"k1":"v31","k2":300,"a1":[{"k1":"v41","k2":400},1,"a",3.14]} || 26 | {"k1":"v1","k2":200} |+------+---------------------------------------------------------------+19 rows in set (0.03 sec)
查询
用json_extract取json内的某个字段
- 获取整个json，$ 在json path中代表root，即整个json
+------+---------------------------------------------------------------+---------------------------------------------------------------+| id | j | json_extract(`j`, '$') |+------+---------------------------------------------------------------+---------------------------------------------------------------+| 1 | NULL | NULL || 2 | null | null || 3 | true | true || 4 | false | false || 5 | 100 | 100 || 6 | 10000 | 10000 || 7 | 1000000000 | 1000000000 || 8 | 1152921504606846976 | 1152921504606846976 || 9 | 6.18 | 6.18 || 10 | "abcd" | "abcd" || 11 | {} | {} || 12 | {"k1":"v31","k2":300} | {"k1":"v31","k2":300} || 13 | [] | [] || 14 | [123,456] | [123,456] || 15 | ["abc","def"] | ["abc","def"] || 16 | [null,true,false,100,6.18,"abc"] | [null,true,false,100,6.18,"abc"] || 17 | [{"k1":"v41","k2":400},1,"a",3.14] | [{"k1":"v41","k2":400},1,"a",3.14] || 18 | {"k1":"v31","k2":300,"a1":[{"k1":"v41","k2":400},1,"a",3.14]} | {"k1":"v31","k2":300,"a1":[{"k1":"v41","k2":400},1,"a",3.14]} || 26 | {"k1":"v1","k2":200} | {"k1":"v1","k2":200} |+------+---------------------------------------------------------------+---------------------------------------------------------------+19 rows in set (0.03 sec)
- 获取k1字段，没有k1字段的行返回NULL
mysql> SELECT id, j, json_extract(j, '$.k1') FROM test_json ORDER BY id;+------+---------------------------------------------------------------+----------------------------+| id | j | json_extract(`j`, '$.k1') |+------+---------------------------------------------------------------+----------------------------+| 1 | NULL | NULL || 2 | null | NULL || 3 | true | NULL || 4 | false | NULL || 5 | 100 | NULL || 6 | 10000 | NULL || 7 | 1000000000 | NULL || 8 | 1152921504606846976 | NULL || 9 | 6.18 | NULL || 10 | "abcd" | NULL || 11 | {} | NULL || 12 | {"k1":"v31","k2":300} | "v31" || 13 | [] | NULL || 14 | [123,456] | NULL || 15 | ["abc","def"] | NULL || 16 | [null,true,false,100,6.18,"abc"] | NULL || 17 | [{"k1":"v41","k2":400},1,"a",3.14] | NULL || 18 | {"k1":"v31","k2":300,"a1":[{"k1":"v41","k2":400},1,"a",3.14]} | "v31" || 26 | {"k1":"v1","k2":200} | "v1" |+------+---------------------------------------------------------------+----------------------------+19 rows in set (0.03 sec)
- 获取顶层数组的第0个元素
mysql> SELECT id, j, json_extract(j, '$[0]') FROM test_json ORDER BY id;+------+---------------------------------------------------------------+----------------------------+| id | j | json_extract(`j`, '$[0]') |+------+---------------------------------------------------------------+----------------------------+| 1 | NULL | NULL || 2 | null | NULL || 3 | true | NULL || 4 | false | NULL || 5 | 100 | NULL || 6 | 10000 | NULL || 7 | 1000000000 | NULL || 8 | 1152921504606846976 | NULL || 9 | 6.18 | NULL || 10 | "abcd" | NULL || 11 | {} | NULL || 12 | {"k1":"v31","k2":300} | NULL || 13 | [] | NULL || 14 | [123,456] | 123 || 15 | ["abc","def"] | "abc" || 16 | [null,true,false,100,6.18,"abc"] | null || 17 | [{"k1":"v41","k2":400},1,"a",3.14] | {"k1":"v41","k2":400} || 18 | {"k1":"v31","k2":300,"a1":[{"k1":"v41","k2":400},1,"a",3.14]} | NULL || 26 | {"k1":"v1","k2":200} | NULL |+------+---------------------------------------------------------------+----------------------------+19 rows in set (0.03 sec)
- 获取整个json array
mysql> SELECT id, j, json_extract(j, '$.a1') FROM test_json ORDER BY id;+------+---------------------------------------------------------------+------------------------------------+| id | j | json_extract(`j`, '$.a1') |+------+---------------------------------------------------------------+------------------------------------+| 1 | NULL | NULL || 2 | null | NULL || 3 | true | NULL || 4 | false | NULL || 5 | 100 | NULL || 6 | 10000 | NULL || 7 | 1000000000 | NULL || 8 | 1152921504606846976 | NULL || 9 | 6.18 | NULL || 10 | "abcd" | NULL || 11 | {} | NULL || 12 | {"k1":"v31","k2":300} | NULL || 13 | [] | NULL || 14 | [123,456] | NULL || 15 | ["abc","def"] | NULL || 16 | [null,true,false,100,6.18,"abc"] | NULL || 17 | [{"k1":"v41","k2":400},1,"a",3.14] | NULL || 18 | {"k1":"v31","k2":300,"a1":[{"k1":"v41","k2":400},1,"a",3.14]} | [{"k1":"v41","k2":400},1,"a",3.14] || 26 | {"k1":"v1","k2":200} | NULL |+------+---------------------------------------------------------------+------------------------------------+19 rows in set (0.02 sec)
- 获取json array中嵌套object的字段
mysql> SELECT id, j, json_extract(j, '$.a1[0]'), json_extract(j, '$.a1[0].k1') FROM test_json ORDER BY id;+------+---------------------------------------------------------------+-------------------------------+----------------------------------+| id | j | json_extract(`j`, '$.a1[0]') | json_extract(`j`, '$.a1[0].k1') |+------+---------------------------------------------------------------+-------------------------------+----------------------------------+| 1 | NULL | NULL | NULL || 2 | null | NULL | NULL || 3 | true | NULL | NULL || 4 | false | NULL | NULL || 5 | 100 | NULL | NULL || 6 | 10000 | NULL | NULL || 7 | 1000000000 | NULL | NULL || 8 | 1152921504606846976 | NULL | NULL || 9 | 6.18 | NULL | NULL || 10 | "abcd" | NULL | NULL || 11 | {} | NULL | NULL || 12 | {"k1":"v31","k2":300} | NULL | NULL || 13 | [] | NULL | NULL || 14 | [123,456] | NULL | NULL || 15 | ["abc","def"] | NULL | NULL || 16 | [null,true,false,100,6.18,"abc"] | NULL | NULL || 17 | [{"k1":"v41","k2":400},1,"a",3.14] | NULL | NULL || 18 | {"k1":"v31","k2":300,"a1":[{"k1":"v41","k2":400},1,"a",3.14]} | {"k1":"v41","k2":400} | "v41" || 26 | {"k1":"v1","k2":200} | NULL | NULL |+------+---------------------------------------------------------------+-------------------------------+----------------------------------+19 rows in set (0.02 sec)
- 获取具体类型的
- json_extract_string 获取string类型字段，非string类型转成string
mysql> SELECT id, j, json_extract_string(j, '$') FROM test_json ORDER BY id;+------+---------------------------------------------------------------+---------------------------------------------------------------+| id | j | json_extract_string(`j`, '$') |+------+---------------------------------------------------------------+---------------------------------------------------------------+| 1 | NULL | NULL || 2 | null | null || 3 | true | true || 4 | false | false || 5 | 100 | 100 || 6 | 10000 | 10000 || 7 | 1000000000 | 1000000000 || 8 | 1152921504606846976 | 1152921504606846976 || 9 | 6.18 | 6.18 || 10 | "abcd" | abcd || 11 | {} | {} || 12 | {"k1":"v31","k2":300} | {"k1":"v31","k2":300} || 13 | [] | [] || 14 | [123,456] | [123,456] || 15 | ["abc","def"] | ["abc","def"] || 16 | [null,true,false,100,6.18,"abc"] | [null,true,false,100,6.18,"abc"] || 17 | [{"k1":"v41","k2":400},1,"a",3.14] | [{"k1":"v41","k2":400},1,"a",3.14] || 18 | {"k1":"v31","k2":300,"a1":[{"k1":"v41","k2":400},1,"a",3.14]} | {"k1":"v31","k2":300,"a1":[{"k1":"v41","k2":400},1,"a",3.14]} || 26 | {"k1":"v1","k2":200} | {"k1":"v1","k2":200} |+------+---------------------------------------------------------------+---------------------------------------------------------------+19 rows in set (0.02 sec)mysql> SELECT id, j, json_extract_string(j, '$.k1') FROM test_json ORDER BY id;+------+---------------------------------------------------------------+-----------------------------------+| id | j | json_extract_string(`j`, '$.k1') |+------+---------------------------------------------------------------+-----------------------------------+| 1 | NULL | NULL || 2 | null | NULL || 3 | true | NULL || 4 | false | NULL || 5 | 100 | NULL || 6 | 10000 | NULL || 7 | 1000000000 | NULL || 8 | 1152921504606846976 | NULL || 9 | 6.18 | NULL || 10 | "abcd" | NULL || 11 | {} | NULL || 12 | {"k1":"v31","k2":300} | v31 || 13 | [] | NULL || 14 | [123,456] | NULL || 15 | ["abc","def"] | NULL || 16 | [null,true,false,100,6.18,"abc"] | NULL || 17 | [{"k1":"v41","k2":400},1,"a",3.14] | NULL || 18 | {"k1":"v31","k2":300,"a1":[{"k1":"v41","k2":400},1,"a",3.14]} | v31 || 26 | {"k1":"v1","k2":200} | v1 |+------+---------------------------------------------------------------+-----------------------------------+19 rows in set (0.03 sec)
- json_extract_int 获取int类型字段，非int类型返回NULL
mysql> SELECT id, j, json_extract_int(j, '$') FROM test_json ORDER BY id;+------+---------------------------------------------------------------+-----------------------------+| id | j | json_extract_int(`j`, '$') |+------+---------------------------------------------------------------+-----------------------------+| 1 | NULL | NULL || 2 | null | NULL || 3 | true | NULL || 4 | false | NULL || 5 | 100 | 100 || 6 | 10000 | 10000 || 7 | 1000000000 | 1000000000 || 8 | 1152921504606846976 | NULL || 9 | 6.18 | NULL || 10 | "abcd" | NULL || 11 | {} | NULL || 12 | {"k1":"v31","k2":300} | NULL || 13 | [] | NULL || 14 | [123,456] | NULL || 15 | ["abc","def"] | NULL || 16 | [null,true,false,100,6.18,"abc"] | NULL || 17 | [{"k1":"v41","k2":400},1,"a",3.14] | NULL || 18 | {"k1":"v31","k2":300,"a1":[{"k1":"v41","k2":400},1,"a",3.14]} | NULL || 26 | {"k1":"v1","k2":200} | NULL |+------+---------------------------------------------------------------+-----------------------------+19 rows in set (0.02 sec)mysql> SELECT id, j, json_extract_int(j, '$.k2') FROM test_json ORDER BY id;+------+---------------------------------------------------------------+--------------------------------+| id | j | json_extract_int(`j`, '$.k2') |+------+---------------------------------------------------------------+--------------------------------+| 1 | NULL | NULL || 2 | null | NULL || 3 | true | NULL || 4 | false | NULL || 5 | 100 | NULL || 6 | 10000 | NULL || 7 | 1000000000 | NULL || 8 | 1152921504606846976 | NULL || 9 | 6.18 | NULL || 10 | "abcd" | NULL || 11 | {} | NULL || 12 | {"k1":"v31","k2":300} | 300 || 13 | [] | NULL || 14 | [123,456] | NULL || 15 | ["abc","def"] | NULL || 16 | [null,true,false,100,6.18,"abc"] | NULL || 17 | [{"k1":"v41","k2":400},1,"a",3.14] | NULL || 18 | {"k1":"v31","k2":300,"a1":[{"k1":"v41","k2":400},1,"a",3.14]} | 300 || 26 | {"k1":"v1","k2":200} | 200 |+------+---------------------------------------------------------------+--------------------------------+19 rows in set (0.03 sec)
- json_extract_bigint 获取bigint类型字段，非bigint类型返回NULL
mysql> SELECT id, j, json_extract_bigint(j, '$') FROM test_json ORDER BY id;+------+---------------------------------------------------------------+--------------------------------+| id | j | json_extract_bigint(`j`, '$') |+------+---------------------------------------------------------------+--------------------------------+| 1 | NULL | NULL || 2 | null | NULL || 3 | true | NULL || 4 | false | NULL || 5 | 100 | 100 || 6 | 10000 | 10000 || 7 | 1000000000 | 1000000000 || 8 | 1152921504606846976 | 1152921504606846976 || 9 | 6.18 | NULL || 10 | "abcd" | NULL || 11 | {} | NULL || 12 | {"k1":"v31","k2":300} | NULL || 13 | [] | NULL || 14 | [123,456] | NULL || 15 | ["abc","def"] | NULL || 16 | [null,true,false,100,6.18,"abc"] | NULL || 17 | [{"k1":"v41","k2":400},1,"a",3.14] | NULL || 18 | {"k1":"v31","k2":300,"a1":[{"k1":"v41","k2":400},1,"a",3.14]} | NULL || 26 | {"k1":"v1","k2":200} | NULL |+------+---------------------------------------------------------------+--------------------------------+19 rows in set (0.03 sec)mysql> SELECT id, j, json_extract_bigint(j, '$.k2') FROM test_json ORDER BY id;+------+---------------------------------------------------------------+-----------------------------------+| id | j | json_extract_bigint(`j`, '$.k2') |+------+---------------------------------------------------------------+-----------------------------------+| 1 | NULL | NULL || 2 | null | NULL || 3 | true | NULL || 4 | false | NULL || 5 | 100 | NULL || 6 | 10000 | NULL || 7 | 1000000000 | NULL || 8 | 1152921504606846976 | NULL || 9 | 6.18 | NULL || 10 | "abcd" | NULL || 11 | {} | NULL || 12 | {"k1":"v31","k2":300} | 300 || 13 | [] | NULL || 14 | [123,456] | NULL || 15 | ["abc","def"] | NULL || 16 | [null,true,false,100,6.18,"abc"] | NULL || 17 | [{"k1":"v41","k2":400},1,"a",3.14] | NULL || 18 | {"k1":"v31","k2":300,"a1":[{"k1":"v41","k2":400},1,"a",3.14]} | 300 || 26 | {"k1":"v1","k2":200} | 200 |+------+---------------------------------------------------------------+-----------------------------------+19 rows in set (0.02 sec)
- json_extract_double 获取double类型字段，非double类型返回NULL
mysql> SELECT id, j, json_extract_double(j, '$') FROM test_json ORDER BY id;+------+---------------------------------------------------------------+--------------------------------+| id | j | json_extract_double(`j`, '$') |+------+---------------------------------------------------------------+--------------------------------+| 1 | NULL | NULL || 2 | null | NULL || 3 | true | NULL || 4 | false | NULL || 5 | 100 | 100 || 6 | 10000 | 10000 || 7 | 1000000000 | 1000000000 || 8 | 1152921504606846976 | 1.152921504606847e+18 || 9 | 6.18 | 6.18 || 10 | "abcd" | NULL || 11 | {} | NULL || 12 | {"k1":"v31","k2":300} | NULL || 13 | [] | NULL || 14 | [123,456] | NULL || 15 | ["abc","def"] | NULL || 16 | [null,true,false,100,6.18,"abc"] | NULL || 17 | [{"k1":"v41","k2":400},1,"a",3.14] | NULL || 18 | {"k1":"v31","k2":300,"a1":[{"k1":"v41","k2":400},1,"a",3.14]} | NULL || 26 | {"k1":"v1","k2":200} | NULL |+------+---------------------------------------------------------------+--------------------------------+19 rows in set (0.02 sec)mysql> SELECT id, j, json_extract_double(j, '$.k2') FROM test_json ORDER BY id;+------+---------------------------------------------------------------+-----------------------------------+| id | j | json_extract_double(`j`, '$.k2') |+------+---------------------------------------------------------------+-----------------------------------+| 1 | NULL | NULL || 2 | null | NULL || 3 | true | NULL || 4 | false | NULL || 5 | 100 | NULL || 6 | 10000 | NULL || 7 | 1000000000 | NULL || 8 | 1152921504606846976 | NULL || 9 | 6.18 | NULL || 10 | "abcd" | NULL || 11 | {} | NULL || 12 | {"k1":"v31","k2":300} | 300 || 13 | [] | NULL || 14 | [123,456] | NULL || 15 | ["abc","def"] | NULL || 16 | [null,true,false,100,6.18,"abc"] | NULL || 17 | [{"k1":"v41","k2":400},1,"a",3.14] | NULL || 18 | {"k1":"v31","k2":300,"a1":[{"k1":"v41","k2":400},1,"a",3.14]} | 300 || 26 | {"k1":"v1","k2":200} | 200 |+------+---------------------------------------------------------------+-----------------------------------+19 rows in set (0.03 sec)
- json_extract_bool 获取bool类型字段，非bool类型返回NULL
mysql> SELECT id, j, json_extract_bool(j, '$') FROM test_json ORDER BY id;+------+---------------------------------------------------------------+------------------------------+| id | j | json_extract_bool(`j`, '$') |+------+---------------------------------------------------------------+------------------------------+| 1 | NULL | NULL || 2 | null | NULL || 3 | true | 1 || 4 | false | 0 || 5 | 100 | NULL || 6 | 10000 | NULL || 7 | 1000000000 | NULL || 8 | 1152921504606846976 | NULL || 9 | 6.18 | NULL || 10 | "abcd" | NULL || 11 | {} | NULL || 12 | {"k1":"v31","k2":300} | NULL || 13 | [] | NULL || 14 | [123,456] | NULL || 15 | ["abc","def"] | NULL || 16 | [null,true,false,100,6.18,"abc"] | NULL || 17 | [{"k1":"v41","k2":400},1,"a",3.14] | NULL || 18 | {"k1":"v31","k2":300,"a1":[{"k1":"v41","k2":400},1,"a",3.14]} | NULL || 26 | {"k1":"v1","k2":200} | NULL |+------+---------------------------------------------------------------+------------------------------+19 rows in set (0.01 sec)mysql> SELECT id, j, json_extract_bool(j, '$[1]') FROM test_json ORDER BY id;+------+---------------------------------------------------------------+---------------------------------+| id | j | json_extract_bool(`j`, '$[1]') |+------+---------------------------------------------------------------+---------------------------------+| 1 | NULL | NULL || 2 | null | NULL || 3 | true | NULL || 4 | false | NULL || 5 | 100 | NULL || 6 | 10000 | NULL || 7 | 1000000000 | NULL || 8 | 1152921504606846976 | NULL || 9 | 6.18 | NULL || 10 | "abcd" | NULL || 11 | {} | NULL || 12 | {"k1":"v31","k2":300} | NULL || 13 | [] | NULL || 14 | [123,456] | NULL || 15 | ["abc","def"] | NULL || 16 | [null,true,false,100,6.18,"abc"] | 1 || 17 | [{"k1":"v41","k2":400},1,"a",3.14] | NULL || 18 | {"k1":"v31","k2":300,"a1":[{"k1":"v41","k2":400},1,"a",3.14]} | NULL || 26 | {"k1":"v1","k2":200} | NULL |+------+---------------------------------------------------------------+---------------------------------+19 rows in set (0.01 sec)
- json_extract_isnull 获取json null类型字段，null返回1，非null返回0
- 需要注意的是json null和SQL NULL不一样，SQL NULL表示某个字段的值不存在，而json null表示值存在但是是一个特殊值null
mysql> SELECT id, j, json_extract_isnull(j, '$') FROM test_json ORDER BY id;+------+---------------------------------------------------------------+--------------------------------+| id | j | json_extract_isnull(`j`, '$') |+------+---------------------------------------------------------------+--------------------------------+| 1 | NULL | NULL || 2 | null | 1 || 3 | true | 0 || 4 | false | 0 || 5 | 100 | 0 || 6 | 10000 | 0 || 7 | 1000000000 | 0 || 8 | 1152921504606846976 | 0 || 9 | 6.18 | 0 || 10 | "abcd" | 0 || 11 | {} | 0 || 12 | {"k1":"v31","k2":300} | 0 || 13 | [] | 0 || 14 | [123,456] | 0 || 15 | ["abc","def"] | 0 || 16 | [null,true,false,100,6.18,"abc"] | 0 || 17 | [{"k1":"v41","k2":400},1,"a",3.14] | 0 || 18 | {"k1":"v31","k2":300,"a1":[{"k1":"v41","k2":400},1,"a",3.14]} | 0 || 26 | {"k1":"v1","k2":200} | 0 |+------+---------------------------------------------------------------+--------------------------------+19 rows in set (0.03 sec)
用json_exists_path检查json内的某个字段是否存在
mysql> SELECT id, j, json_exists_path(j, '$') FROM test_json ORDER BY id;+------+---------------------------------------------------------------+-----------------------------+| id | j | json_exists_path(`j`, '$') |+------+---------------------------------------------------------------+-----------------------------+| 1 | NULL | NULL || 2 | null | 1 || 3 | true | 1 || 4 | false | 1 || 5 | 100 | 1 || 6 | 10000 | 1 || 7 | 1000000000 | 1 || 8 | 1152921504606846976 | 1 || 9 | 6.18 | 1 || 10 | "abcd" | 1 || 11 | {} | 1 || 12 | {"k1":"v31","k2":300} | 1 || 13 | [] | 1 || 14 | [123,456] | 1 || 15 | ["abc","def"] | 1 || 16 | [null,true,false,100,6.18,"abc"] | 1 || 17 | [{"k1":"v41","k2":400},1,"a",3.14] | 1 || 18 | {"k1":"v31","k2":300,"a1":[{"k1":"v41","k2":400},1,"a",3.14]} | 1 || 26 | {"k1":"v1","k2":200} | 1 |+------+---------------------------------------------------------------+-----------------------------+19 rows in set (0.02 sec)mysql> SELECT id, j, json_exists_path(j, '$.k1') FROM test_json ORDER BY id;+------+---------------------------------------------------------------+--------------------------------+| id | j | json_exists_path(`j`, '$.k1') |+------+---------------------------------------------------------------+--------------------------------+| 1 | NULL | NULL || 2 | null | 0 || 3 | true | 0 || 4 | false | 0 || 5 | 100 | 0 || 6 | 10000 | 0 || 7 | 1000000000 | 0 || 8 | 1152921504606846976 | 0 || 9 | 6.18 | 0 || 10 | "abcd" | 0 || 11 | {} | 0 || 12 | {"k1":"v31","k2":300} | 1 || 13 | [] | 0 || 14 | [123,456] | 0 || 15 | ["abc","def"] | 0 || 16 | [null,true,false,100,6.18,"abc"] | 0 || 17 | [{"k1":"v41","k2":400},1,"a",3.14] | 0 || 18 | {"k1":"v31","k2":300,"a1":[{"k1":"v41","k2":400},1,"a",3.14]} | 1 || 26 | {"k1":"v1","k2":200} | 1 |+------+---------------------------------------------------------------+--------------------------------+19 rows in set (0.03 sec)mysql> SELECT id, j, json_exists_path(j, '$[2]') FROM test_json ORDER BY id;+------+---------------------------------------------------------------+--------------------------------+| id | j | json_exists_path(`j`, '$[2]') |+------+---------------------------------------------------------------+--------------------------------+| 1 | NULL | NULL || 2 | null | 0 || 3 | true | 0 || 4 | false | 0 || 5 | 100 | 0 || 6 | 10000 | 0 || 7 | 1000000000 | 0 || 8 | 1152921504606846976 | 0 || 9 | 6.18 | 0 || 10 | "abcd" | 0 || 11 | {} | 0 || 12 | {"k1":"v31","k2":300} | 0 || 13 | [] | 0 || 14 | [123,456] | 0 || 15 | ["abc","def"] | 0 || 16 | [null,true,false,100,6.18,"abc"] | 1 || 17 | [{"k1":"v41","k2":400},1,"a",3.14] | 1 || 18 | {"k1":"v31","k2":300,"a1":[{"k1":"v41","k2":400},1,"a",3.14]} | 0 || 26 | {"k1":"v1","k2":200} | 0 |+------+---------------------------------------------------------------+--------------------------------+19 rows in set (0.02 sec)
用json_type获取json内的某个字段的类型
- 返回json path对应的json字段类型，如果不存在返回NULL
mysql> SELECT id, j, json_type(j, '$') FROM test_json ORDER BY id;+------+---------------------------------------------------------------+----------------------+| id | j | json_type(`j`, '$') |+------+---------------------------------------------------------------+----------------------+| 1 | NULL | NULL || 2 | null | null || 3 | true | bool || 4 | false | bool || 5 | 100 | int || 6 | 10000 | int || 7 | 1000000000 | int || 8 | 1152921504606846976 | bigint || 9 | 6.18 | double || 10 | "abcd" | string || 11 | {} | object || 12 | {"k1":"v31","k2":300} | object || 13 | [] | array || 14 | [123,456] | array || 15 | ["abc","def"] | array || 16 | [null,true,false,100,6.18,"abc"] | array || 17 | [{"k1":"v41","k2":400},1,"a",3.14] | array || 18 | {"k1":"v31","k2":300,"a1":[{"k1":"v41","k2":400},1,"a",3.14]} | object || 26 | {"k1":"v1","k2":200} | object |+------+---------------------------------------------------------------+----------------------+19 rows in set (0.02 sec)mysql> select id, j, json_type(j, '$.k1') from test_json order by id;+------+---------------------------------------------------------------+-------------------------+| id | j | json_type(`j`, '$.k1') |+------+---------------------------------------------------------------+-------------------------+| 1 | NULL | NULL || 2 | null | NULL || 3 | true | NULL || 4 | false | NULL || 5 | 100 | NULL || 6 | 10000 | NULL || 7 | 1000000000 | NULL || 8 | 1152921504606846976 | NULL || 9 | 6.18 | NULL || 10 | "abcd" | NULL || 11 | {} | NULL || 12 | {"k1":"v31","k2":300} | string || 13 | [] | NULL || 14 | [123,456] | NULL || 15 | ["abc","def"] | NULL || 16 | [null,true,false,100,6.18,"abc"] | NULL || 17 | [{"k1":"v41","k2":400},1,"a",3.14] | NULL || 18 | {"k1":"v31","k2":300,"a1":[{"k1":"v41","k2":400},1,"a",3.14]} | string || 26 | {"k1":"v1","k2":200} | string |+------+---------------------------------------------------------------+-------------------------+19 rows in set (0.03 sec)
keywords
JSON, json_parse, json_parse_error_to_null, json_parse_error_to_value, json_extract, json_extract_isnull, json_extract_bool, json_extract_int, json_extract_bigint, json_extract_double, json_extract_string, json_exists_path, json_type
