What is the use of Json_merge functions in MySQL?

Requirements Description :

With the Json_merge function in MySQL, you can combine multiple JSON objects into one object

Operation Process :

1. View a table with JSON columns

Mysql> SELECT * from tab_json;+----+--------------------------------------------------------------------------- --------+| ID | Data |+----+---------------------------------  --------------------------------------------------+| 1 |  {"Tel": "132223232444", "name": "David", "Address": "Beijing"} | | 2 |  {"Tel": "13390989765", "name": "Mike", "Address": "Guangzhou"} | | 3 |  {"Names": "Smith"} | | 4 |  {"Names": "Smith", "Address": "Beijing"} | | 5 |  {"Names": "Smith", "Address": "Beijing", "Birthday": "2018-09-09"} | | 6 |  {"Max": "true", "names": "Smith", "Address": "Beijing", "Birthday": "2018-09-09"} | | 7 |  {"Max": "True", "names": "Smith", "Address": "Beijing", "Birthday": "2018-09-09"} | | 8 | {"Oax": "true", "names": "Smith", "Address": "Beijing", "BirThday ":" 2018-09-09 "} |+----+----------------------------------------------------------------------------------- +8 rows in Set (0.00 sec)

2. Merges the value of names with the value of address

Mysql> Select Json_extract (data, ' $.names '), json_extract (data, ' $.address ') from tab_json;+---------------------- --------+--------------------------------+| Json_extract (data, ' $.names ') | Json_extract (data, ' $.address ') |+------------------------------+--------------------------------+| NULL | "Beijing" | | NULL | "Guangzhou" | | "Smith" | NULL | | "Smith" | "Beijing" | | "Smith" | "Beijing" | | "Smith" | "Beijing" | | "Smith" | "Beijing" | | "Smith" | "Beijing" |+------------------------------+--------------------------------+8 rows in Set (0.00 sec) m Ysql> SelectJson_merge(Json_extract (data, ' $.names '), json_extract (data, ' $.address ')) from tab_json;+----------------------------------- --------------------------------------+| Json_merge (json_extract (data, ' $.names '), json_extract (data, ' $.address ')) |+------------------------------------- ------------------------------------+| NULL | | NULL | | NULL | | ["Smith", "Beijing"] | | ["Smith", "Beijing"] | | ["Smith", "Beijing"] | | ["Smith", "Beijing"] | | ["Smith", "Beijing"] |+------------------------------------------------ -------------------------+8 rows in Set (0.00 sec) 

3. If multiple objects contain the same key, they are also merged into a specific values

mysql> SELECT json_merge ('{"a": 1, "B": 2}', '"a": 4}[1, 4], "B": 2, "C": 3}                      |+----------------------------------------------------+1 row in Set (0.00 sec)

Note: Combining the values of two objects into one, the value of a key also increases to 2.

Document created: June 6, 2018 17:49:18

What is the use of Json_merge functions in MySQL?