How to edit a JSON document in MySQL

- 3 minutes read - 543 words

You can edit a JSON document in MySQL with:

  • The JSON_SET function that will replace values for JSON paths that exists and add values for the ones that don’t exist.
  • The JSON_REPLACE function that will replace values for JSON paths that exists and ignore the ones that don’t exist.

NOTE: more info is available in the MySQL JSON functions documentation page

The dataset

The dataset is the following:

{
    "id": 778,
    "shop": "Luigis Pizza",
    "name": "Edward Olson",
    "phoneNumbers":
        ["(935)503-3765x4154","(935)12345"],
    "address": "Unit 9398 Box 2056 DPO AP 24022",
    "image": null,
    "pizzas": [
        {
            "pizzaName": "Salami",
            "additionalToppings": ["🥓", "🌶️"]
        },
        {
            "pizzaName": "Margherita",
            "additionalToppings": ["🍌", "🌶️", "🍍"]
        }
    ]
}
Check out the description of the fields The following examples use a pizza order dataset with an order having:
  • id: 778
  • shop: “Luigis Pizza”
  • name: “Edward Olson”
  • phoneNumbers:["(935)503-3765x4154","(935)12345"]
  • address: “Unit 9398 Box 2056 DPO AP 24022”
  • image: null
  • and two pizzas contained in the pizzas item:
[
    {
        "pizzaName": "Salami",
        "additionalToppings": ["🥓", "🌶️"]
    },
    {
        "pizzaName": "Margherita",
        "additionalToppings": ["🍌", "🌶️", "🍍"]
    }
]
If you want to reproduce the examples, check how to recreate the dataset

It can be recreated with the following script:

create table test(id serial primary key, json_data json);

insert into test(json_data) values (
'{
    "id": 778,
    "shop": "Luigis Pizza",
    "name": "Edward Olson",
    "phoneNumbers":
        ["(935)503-3765x4154","(935)12345"],
    "address": "Unit 9398 Box 2056 DPO AP 24022",
    "image": null,
    "pizzas": [
        {
            "pizzaName": "Salami",
            "additionalToppings": ["🥓", "🌶️"]
        },
        {
            "pizzaName": "Margherita",
            "additionalToppings": ["🍌", "🌶️", "🍍"]
        }
    ]
}');

Edit a JSON document with JSON_SET function

To edit a JSON document you can use the JSON_SET function. To replace the second pizzaName from Margherita to Capricciosa you can

select 
    JSON_SET(json_data,'$.pizzas[1].pizzaName','Capricciosa') from test;

Where

  • json_data is the JSON column
  • $.pizzas[1].pizzaName selects the pizzas item, the 2nd element in the array and the pizzaName subitem
  • the last parameter Capricciosa represents the value to replace

Result

+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| {"id": 778, "name": "Edward Olson", "shop": "Luigis Pizza", "image": null, "pizzas": [{"pizzaName": "Salami", "additionalToppings": ["🥓", "🌶️"]}, {"pizzaName": "Capricciosa", "additionalToppings": ["🍌", "🌶️", "🍍"]}], "address": "Unit 9398 Box 2056 DPO AP 24022", "phoneNumbers": ["(935)503-3765x4154", "(935)12345"]}                         |
+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

Edit a JSON document with JSON_REPLACE function

To edit a JSON document you can use the JSON_REPLACE function. To replace the second pizzaName from Margherita to Capricciosa you can

select 
    JSON_REPLACE(json_data,'$.pizzas[1].pizzaName','Capricciosa') from test;

Where

  • json_data is the JSON column
  • $.pizzas[1].pizzaName selects the pizzas item, the 2nd element in the array and the pizzaName subitem
  • the last parameter Capricciosa represents the value to replace

Result

+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| JSON_REPLACE(json_data,'$.pizzas[1].pizzaName','Capricciosa')                                                                                                                                                                                                                                                                                   |
+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| {"id": 778, "name": "Edward Olson", "shop": "Luigis Pizza", "image": null, "pizzas": [{"pizzaName": "Salami", "additionalToppings": ["🥓", "🌶️"]}, {"pizzaName": "Capricciosa", "additionalToppings": ["🍌", "🌶️", "🍍"]}], "address": "Unit 9398 Box 2056 DPO AP 24022", "phoneNumbers": ["(935)503-3765x4154", "(935)12345"]}                         |
+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

Note: If you try to use the JSON_REPLACE with a non existing field, like the $.nameS, the function will NOT edit the document.

select 
    JSON_REPLACE(json_data,'$.nameS','Ugo') from test;

The above doesn’t edit the document since the key nameS is not present

+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| JSON_REPLACE(json_data,'$.nameS','Ugo')                                                                                                                                                                                                                                                                                                        |
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| {"id": 778, "name": "Edward Olson", "shop": "Luigis Pizza", "image": null, "pizzas": [{"pizzaName": "Salami", "additionalToppings": ["🥓", "🌶️"]}, {"pizzaName": "Margherita", "additionalToppings": ["🍌", "🌶️", "🍍"]}], "address": "Unit 9398 Box 2056 DPO AP 24022", "phoneNumbers": ["(935)503-3765x4154", "(935)12345"]}                         |
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

Review all the JSON MySQL use-cases listed in the main page