Python SQLAlchemy and Postgres - How to query a JSON element

Question

Let\'s say I have a Postgres database (9.3) and there is a table called Resources. In the Resources table I have the fields id which is an

Answer 1

If you are using JSON type (not JSONB) the following worked for me:

Note the '"object"'

    query = db.session.query(ProductSchema).filter(
        cast(ProductSchema.ProductJSON["type"], db.String) != '"object"'
    )

Answer 2

According sqlalchemy.types.JSON, you can do it like this

from sqlalchemy import JSON
from sqlalchemy import cast
records = db_session.query(Resource).filter(Resources.data["lastname"] == cast("Doe", JSON)).all()

Answer 3

Also you could explicitly cast string to JSON (see Postgres JSON type doc).

from sqlalchemy.dialects.postgres import JSON
from sqlalchemy.sql.expression import cast
db_session.query(Resource).filter(
    Resources.data["lastname"] == cast("Doe", JSON)
).all()

Answer 4

Try using astext

records = db_session.query(Resource).filter(
              Resources.data["lastname"].astext == "Doe"
          ).all()

Please note that the column MUST have a type of a JSONB. The regular JSON column will not work.