How to remove a field in a JSON document in MySQL

- 2 minutes read - 354 words

You can remove a field from JSON document in MySQL with the JSON_REMOVE function.

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

 

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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": ["🍌", "🌶️", "🍍"]
        }
    ]
}');

Remove a field from a JSON document with JSON_REMOVE function

To remove one or more fields from a JSON document you can use the JSON_REMOVE function. To remove the the pizzaName from the second pizza in the above order you can:

select 
    JSON_REMOVE(json_data,'$.pizzas[1].pizzaName') remove_pizzaName 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

Result

+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| remove_pizzaName                                                                                                                                                                                                                                                                                                    |
+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| {"id": 778, "name": "Edward Olson", "shop": "Luigis Pizza", "image": null, "pizzas": [{"pizzaName": "Salami", "additionalToppings": ["🥓", "🌶️"]}, {"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