Question

when i have a table in MySQL:

create table t
(
    id integer primary key,
    time datetime not null,
    value integer not null
)

and an mapping class:

class T(Base):
    __tablename__ = 't'

    id = Column(INTEGER, primary_key=True, nullable=False, unique=True)
    time = Column(DATETIME, nullable=False)
    value = Column(INTEGER, nullable=False)

how can i select all values that have given month from this table using SQLAlchemy?
MySQL has the month function: select value from t where month(time) = 4
but SQLAlchemy has no month function.

Answer 1

Without loading all Ts into the session, one can use Functions to filter non April objects straight-away:

from sqlalchemy.sql import func
qry = session.query(T).filter(func.MONTH(T.time) == 4)
for t in qry:
    print t.value