How could i get the sqlite date delta in SQLAlchemy -

i have sqlite table column final_date in integer type (use date). want calculate number of days column now. in sqlite, can run sql of function (julianday) following.

select (julianday(final_date) - julianday('now')) days bond days > 0 109.407374872826 482.407374872826 488.407374872826 .... 

however, in sqlalchemy, code following can not accurate number of days.

today = datetime.today().date()

query = session.query( bond.final_date - today )

i wonder whether there effective way apply function julianday sqlalchemy code or whether there alternative native approach in sqlalchemy accomplish this.

if have control on database , data - may want update schema define column sqlalchemy.types.datetime. use datetime module make calculations dates.

or can use sqlalchemy.sql.func access julianday() sqlite function.

from sqlalchemy.sql import func q = session.query( func.julianday( bond.final_date) - func.julianday("now")) row in q.all():     print row[0] 

please note second approach uses sqlite specific function , won't work other database systems.