无法从Postgres中的JSON列中提取数据

Question

I have a JSON column as shown below. I am trying to extract values for ID and identifier columns (namely identifier1, identifier2, identifier3 and identifier4) but I am unable to get the data. Given below is a sample of the JSON data I am trying to extract from.

[{"id": 5079, "identifier1": {"key": "ABC", "type": "identifier", "regex": null}, 
"identifier2": {"key": 123, "type": "identifier", "regex": null}, 
"identifier3": {"key": XYZ, "type": "identifier", "regex": null}, 
"identifier4": {"key": ABC, "type": "identifier", "regex": null}}]

Data type of the column is JSONB DB : Postgres ColumnName: jsondata

I tried the below query but that returned a null output

select
    jsondata ->> 'id',
    jsondata -> 'identifier1' ->> 'key'
from Customer;

Could any one help me on how this can be extracted. Thanks

Answer 1

I'm not sure if I got your question right, but I guess what you're looking for is something like this:

SELECT 
  json_array_elements(jsondata)->>'id' AS id,
 (json_array_elements(jsondata)->>'identifier1')::json ->> 'key'  AS key1,
 (json_array_elements(jsondata)->>'identifier2')::json ->> 'key'  AS key2,
 (json_array_elements(jsondata)->>'identifier3')::json ->> 'key'  AS key3,
 (json_array_elements(jsondata)->>'identifier4')::json ->> 'key'  AS key4
from Customer;