几种常见sqlalchemy查询：
1 #简单查询 2 print(session.query(User).all()) 3 print(session.query(User.name, User.fullname).all()) 4 print(session.query(User, User.name).all()) 5 6 #带条件查询 7 print(session.query(User).filter_by(name='user1').all()) 8 print(session.query(User).filter(User.name == "user").all()) 9 print(session.query(User).filter(User.name.like("user%")).all()) 10 11 #多条件查询 12 print(session.query(User).filter(and_(User.name.like("user%"), User.fullname.like("first%"))).all()) 13 print(session.query(User).filter(or_(User.name.like("user%"), User.password != None)).all()) 14 15 #sql过滤 16 print(session.query(User).filter("id>:id").params(id=1).all()) 17 18 #关联查询 19 print(session.query(User, Address).filter(User.id == Address.user_id).all()) 20 print(session.query(User).join(User.addresses).all()) 21 print(session.query(User).outerjoin(User.addresses).all()) 22 23 #聚合查询 24 print(session.query(User.name, func.count('*').label("user_count")).group_by(User.name).all()) 25 print(session.query(User.name, func.sum(User.id).label("user_id_sum")).group_by(User.name).all()) 26 27 #子查询 28 stmt = session.query(Address.user_id, func.count('*').label("address_count")).group_by(Address.user_id).subquery() 29 print(session.query(User, stmt.c.address_count).outerjoin((stmt, User.id == stmt.c.user_id)).order_by(User.id).all()) 30 31 #exists 32 print(session.query(User).filter(exists().where(Address.user_id == User.id))) 33 print(session.query(User).filter(User.addresses.any()))
限制返回字段查询
1person = session.query(Person.name, Person.created_at, 2 Person.updated_at).filter_by(name="zhongwei").order_by( 3 Person.created_at).first()
记录总数查询：
1from sqlalchemy import func 2 3# count User records, without 4# using a subquery. 5session.query(func.count(User.id)) 6 7# return count of user "id" grouped 8# by "name" 9session.query(func.count(User.id)).\ 10 group_by(User.name) 11 12from sqlalchemy import distinct 13 14# count distinct "name" values 15session.query(func.count(distinct(User.name)))