Check if field exists in json type column PostgreSQL

Question

How do you check if a json field in Postgres has a certain element?

I have tried with json->>'attribute' is not null and doesn't work.

Answer 1

use ->:

where (json->'attribute') is not null 

Answer 2

While this works. It is better to use special operator ?:

WHERE your_column_name::jsonb ? 'attribute' 

NOTE: Only for jsonb type.