How to tabulate a JSON document in MySQL

- 2 minutes read - 343 words

You can tabulate a JSON document (retrieve it as a row) in MySQL with the JSON_TABLE function.

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": ["🍌", "🌶️", "🍍"]  }  ] }');

Tabulate a JSON document with JSON_TABLE function

To retrieve one or more JSON documents as columns and rows you can use the JSON_TABLE function. To retrieve the list of pizzas and their first additional topping from the above as table you can:

select tbl.* from  test,  JSON_TABLE(  json_data,  '$.pizzas[*]'  COLUMNS (  pizzaName VARCHAR(100) PATH '$.pizzaName',  additionalToppings VARCHAR(100) PATH '$.additionalToppings[0]'  )  ) tbl;

Where

  • json_data is the JSON column
  • '$.pizzas[*]' generates a row for each pizza in the pizzas array
  • pizzaName VARCHAR(100) PATH '$.pizzaName' retrieves the pizzaName field
  • additionalToppings VARCHAR(100) PATH '$.additionalToppings[0]' retrieves the first element ([0]) of the additionalToppings array

Result

+------------+--------------------+ | pizzaName | additionalToppings | +------------+--------------------+ | Salami | 🥓 | | Margherita | 🍌 | +------------+--------------------+

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