Select in nested jsonb - postgresql - sql

Question

I had a hard time finding the values on a basis, as all the examples cite the same way of finding information in simple jsons.
But a friend from work gave me a solution and I came to share.
the initial question was: How to make a select in a nested json ???
A json like this:
{
"vehicle":[
{
"vehicle_type":"Truck",
"car_make":"Lotus",
"car_model":"Esprit",
"quantity":7,
"seats":7,
"price_hour":16,
"price_day":147,
"color":[
"Purple",
"Pink",
"Blue",
"White"
]
}
]
}
To view the structure, you can use the https://jsoneditoronline.org/

Answer 1

The answer I bring uses select with regex:
select * from example
where example.jsonTest->>'vehicle' ~ 'color"\s*:\s*"?.*?Blue.*"?';
and
select * from example
where example.jsonTest->>'vehicle' ~ 'vehicle_type"\s*:\s*"?.*?SUV.*"?';
To be clear I left a working example in https://rextester.com/BQZP48785
** sorry for my bad english

Answer 2

In order to determine the vehicle with color blue, and vehicle type with SUV, jsonb_array_elements() function might be used to unnest the main array, and then putting (j.elm->>'vehicle_type') = 'SUV' into the WHERE clause would be enough for the second, while (j.elm->>'color')::jsonb ? 'Blue' should be used containing jsonb conversion with ? operator for the first one, since (j.elm->>'color') extracts an array, while (j.elm->>'vehicle_type') does simple string pieces.
Therefore a regular expression is not needed such as below queries :
SELECT e.*
FROM example e
CROSS JOIN jsonb_array_elements(jsonTest->'vehicle') j(elm)
WHERE (j.elm->>'color')::jsonb ? 'Blue'
and
SELECT e.*
FROM example e
CROSS JOIN jsonb_array_elements(jsonTest->'vehicle') j(elm)
WHERE (j.elm->>'vehicle_type') = 'SUV'
Demo