How to give column name dynamically from string variable in sql alchemy filter?

Question

I want to create query in sql alchemy filter, but column is(dynamic) in variable/specified in variable.

Original Query:

db_session.query(Notice).filter(Notice.subject.like("%" +query+ "%"))

I want to do query like this:

col_name='subject'
db_session.query(Notice).filter(Notice.col_name.like("%" +query+ "%"))
col_name='status'
status=0
db_session.query(Notice).filter(Notice.col_name != 1)

Asked By: anils

||

Source

Answer 1

Just use getattr standard python library function to get an attribute by name:

col_name = 'subject'
db_session.query(Notice).filter(getattr(Notice, col_name).like("%" + query + "%"))

Answered By: van

Answer 2

In newer sqlalchemy version, it should be done this way:

Notice.__table__.c[col_name]

So:

(db_session
    .query(Notice)
    .filter(Notice.__table__.c[col_name].like("%" + query + "%")
)

Answered By: Derek 朕會功夫

Answer 3

The accepted answer has a solution, but an outdated one.

SQLAlchemy 1.3 suggests putting all text filters in text(), joined with and.
Docs

Example: session.query(User).filter(text("id<224")).order_by(text("id")).all()

Another example from docs on a different query

>>> s = select([
...        text("users.fullname || ', ' || addresses.email_address AS title")
...     ]).
...         where(
...             and_(
...                 text("users.id = addresses.user_id"),
...                 text("users.name BETWEEN 'm' AND 'z'"),
...                 text(
...                     "(addresses.email_address LIKE :x "
...                     "OR addresses.email_address LIKE :y)")
...             )
...         ).select_from(text('users, addresses'))

Answered By: Tom Wojcik

Answer 4

I tried @vans solution but it didn’t work. I always got an AttributeError complaining that my table didn’t have that column. What worked for me was table.columns:

getattr(Notice.columns,col_name)

Answered By: dakes

How to give column name dynamically from string variable in sql alchemy filter?

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