嵌套 jsonb 中的 Select - postgresql

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' (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