PostgreSQL® offers two types of data types to handle JSON data, JSON
and JSONB
, you can use the function to_json
(to_jsonb
for JSONB
) to convert a table row to a JSON object.
NOTE: To review the differences between
JSON
andJSONB
check out the related article.
NOTE: more info is available in the PostgreSQL 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\nDPO 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
: 778shop
: “Luigis Pizza”name
: “Edward Olson”phoneNumbers
:["(935)503-3765x4154","(935)12345"]address
: “Unit 9398 Box 2056\nDPO 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, json_data jsonb);
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\nDPO AP 24022",
"image": null,
"pizzas": [
{
"pizzaName": "Salami",
"additionalToppings": ["🥓", "🌶️"]
},
{
"pizzaName": "Margherita",
"additionalToppings": ["🍌", "🌶️", "🍍"]
}
]
}');
Convert a table row to JSON in PostgreSQL with the to_json
function
To convert a table row to json, use the to_json
function (to_jsonb
to create the JSONB equivalent)
select
to_jsonb(
row(33,
'the pizza is in the oven'::text,
ARRAY[11,22,33,44,55])) as res_json;
Result
res_json
--------------------------------------------------------------------------
{"f1": 33, "f2": "the pizza is in the oven", "f3": [11, 22, 33, 44, 55]}
(1 row)
Review all the JSON PostgreSQL use-cases listed in the main page