Filter with Array column with Postgres and SQLAlchemy

Question

I have a simple table with an int[] column, and I'd like to be able to select rows where any one of their array elements matches a value I have, and I cannot figure out how to do this using SQLAlchemy without just using a raw query, which I do not want to do.

Here is the schema for the table ("testuser"):

 Column  |          Type          |
---------+------------------------+
 id      | integer                |
 name    | character varying(250) |
 numbers | integer[]              |

Here is what it looks like with sample data:

 id |  name   |    numbers
----+---------+---------------
  1 | David   | {25,33,42,55}
  2 | Salazar | {11,33,7,19}
  3 | Belinda | {32,6,20,23}
  4 | Casey   | {19,20,27,8}
  5 | Kathie  | {25,31,10,40}
  6 | Dianne  | {25,20,40,39}
  7 | Cortez  | {1,20,18,38}

Here is an SQL statement that generates what I want; I want to do this all in Python without simply writing the raw query (25 is just used as an example).

scrape=# select * from testuser where 25 = ANY(numbers);
 id |  name  |    numbers
----+--------+---------------
  5 | Kathie | {25,31,10,40}
  6 | Dianne | {25,20,40,39}
  1 | David  | {25,33,42,55}
(3 rows)

Another way I found to write it:

scrape=# select * from testuser where numbers @> ARRAY[25];
 id |  name  |    numbers
----+--------+---------------
  5 | Kathie | {25,31,10,40}
  6 | Dianne | {25,20,40,39}
  1 | David  | {25,33,42,55}
(3 rows)

Here is the Python code I used to generate the table:

from sqlalchemy import Column, Integer, String
from sqlalchemy.dialects import postgresql
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker

Base = declarative_base()

class TestUser(Base):
    __tablename__ = 'testuser'
    id = Column(Integer, primary_key=True)
    name = Column(String(250))
    numbers = Column(postgresql.ARRAY(Integer))

engine = create_engine('postgresql://postgres:{pw}@localhost:5432/scrape'.format(pw=POSTGRES_PASSWORD))

Base.metadata.create_all(engine)

DBSession = sessionmaker(bind=engine)
session = DBSession()

testcases = [{"numbers": [25, 33, 42, 55], "name": "David"}, {"numbers": [11, 33, 7, 19 ], "name":     "Salazar"}, {"numbers": [32, 6, 20, 23 ], "name": "Belinda"}, {"numbers": [19, 20, 27, 8 ], "name": "Casey"},     {"numbers": [25, 31, 10, 40 ], "name": "Kathie"}, {"numbers": [25, 20, 40, 39 ], "name": "Dianne"},     {"numbers": [1, 20, 18, 38 ], "name": "Cortez"} ]

for t in testcases:
    session.add(TestUser(name=t['name'], numbers=t['numbers']))
session.commit()

Answer 1

So you want to use the Postgres Array Comparator.

query = session.query(TestUser).filter(TestUser.numbers.contains([some_int])).all()

or

query = session.query(TestUser).filter(TestUser.numbers.any(25)).all()

Answer 2

Damn SQLAlchemy, took me some time to figure out that the correct way will be:

TelegramUser.query.filter(TelegramUser.selected_exchanges.contains(f"{{{platform_name}}}")).all()

Where the platform_name is a str and the selected_exchanges column is defined as follows:

from sqlalchemy.dialects import postgresql as pg

selected_exchanges = db.Column(pg.ARRAY(db.String, dimensions=1), nullable=True)