SqlAlchenmy基本使用

   #简单查询

    print(session.query(User).all())

    print(session.query(User.name, User.fullname).all())

    print(session.query(User, User.name).all())

    #带条件查询

    print(session.query(User).filter_by(name='user1').all())

    print(session.query(User).filter(User.name == "user").all())

    print(session.query(User).filter(User.name.like("user%")).all())

    #多条件查询

    print(session.query(User).filter(and_(User.name.like("user%"), User.fullname.like("first%"))).all())

    print(session.query(User).filter(or_(User.name.like("user%"), User.password != None)).all())

    #sql过滤

    print(session.query(User).filter("id>:id").params(id=1).all())

    #关联查询

    print(session.query(User, Address).filter(User.id == Address.user_id).all())

    print(session.query(User).join(User.addresses).all())

    print(session.query(User).outerjoin(User.addresses).all())

    #聚合查询

    print(session.query(User.name, func.count('*').label("user_count")).group_by(User.name).all())

    print(session.query(User.name, func.sum(User.id).label("user_id_sum")).group_by(User.name).all())

    #子查询

    stmt = session.query(Address.user_id, func.count('*').label("address_count")).group_by(Address.user_id).subquery()

    print(session.query(User, stmt.c.address_count).outerjoin((stmt, User.id == stmt.c.user_id)).order_by(User.id).all())

    #exists

    print(session.query(User).filter(exists().where(Address.user_id == User.id)))

    print(session.query(User).filter(User.addresses.any()))

多条件查询例子：

from sqlalchemy import and_

words = ['%三%', '%猫%']

rule = and_(*[table.u_name.like(w) for w in words])

table.query.filter(rule)

限制返回字段查询

person = session.query(Person.name, Person.created_at,

             Person.updated_at).filter_by(name="zhongwei").order_by(

             Person.created_at).first()

记录总数查询：

from sqlalchemy import func

# count User records, without

# using a subquery.

session.query(func.count(User.id))

# return count of user "id" grouped

# by "name"

session.query(func.count(User.id)).\

        group_by(User.name)

from sqlalchemy import distinct

# count distinct "name" values

session.query(func.count(distinct(User.name)))

　　

Sqlalchemy查询的like mysql order by desc 倒叙排例子

　　

res  =Session.query(OnlineHistoryInfo).order_by(OnlineHistoryInfo.id.desc()).all()

for i in res:

    print (i.task_run_user,i.id)

　

#网上的例子
query = (model.Session.query(model.Entry)

        .join(model.ClassificationItem)

        .join(model.EnumerationValue)

        .filter_by(id=c.row.id)

        .order_by(model.Entry.amount.desc())

        )