#高级版查询操作,厉害了哦#老规矩

from my_create_table importUser,enginefrom sqlalchemy.orm importsessionmaker

Session=sessionmaker(engine)

db_session=Session()#查询数据表操作#and or

from sqlalchemy.sql importand_ , or_

ret= db_session.query(User).filter(and_(User.id > 3, User.name == 'DragonFire')).all()

ret= db_session.query(User).filter(or_(User.id < 2, User.name == 'DragonFire')).all()#查询所有数据

r1 =db_session.query(User).all()#查询数据 指定查询数据列 加入别名

r2 = db_session.query(User.name.label('username'), User.id).first()print(r2.id,r2.username) #15 NBDragon

#表达式筛选条件

r3 = db_session.query(User).filter(User.name == "DragonFire").all()#原生SQL筛选条件

r4 = db_session.query(User).filter_by(name='DragonFire').all()

r5= db_session.query(User).filter_by(name='DragonFire').first()#字符串匹配方式筛选条件 并使用 order_by进行排序

r6 = db_session.query(User).filter(text("id<:value and name=':name")).params(value=224,'>

r7 = db_session.query(User).from_statement(text("SELECT * FROM User where name=:name")).params(name='DragonFire').all()#筛选查询列#query的时候我们不在使用User ORM对象,而是使用User.name来对内容进行选取

user_list =db_session.query(User.name).all()print(user_list)for row inuser_list:print(row.name)#别名映射 name as nick

user_list = db_session.query(User.name.label("nick")).all()print(user_list)for row inuser_list:print(row.nick) #这里要写别名了

#筛选条件格式

user_list = db_session.query(User).filter(User.name == "DragonFire").all()

user_list= db_session.query(User).filter(User.name == "DragonFire").first()

user_list= db_session.query(User).filter_by(name="DragonFire").first()for row inuser_list:print(row.nick)#复杂查询

from sqlalchemy.sql importtext

user_list= db_session.query(User).filter(text("id<:value and name=':name")).params(value=3,name="DragonFire")#查询语句</p'>

from sqlalchemy.sql importtext

user_list= db_session.query(User).filter(text("select * from User id<:value and name=':name")).params(value=3,name="DragonFire")#排序' :>

user_list =db_session.query(User).order_by(User.id).all()

user_list=db_session.query(User).order_by(User.id.desc()).all()for row inuser_list:print(row.name,row.id)#其他查询条件

"""ret = session.query(User).filter_by(name='DragonFire').all()

ret = session.query(User).filter(User.id > 1, User.name == 'DragonFire').all()

ret = session.query(User).filter(User.id.between(1, 3), User.name == 'DragonFire').all() # between 大于1小于3的

ret = session.query(User).filter(User.id.in_([1,3,4])).all() # in_([1,3,4]) 只查询id等于1,3,4的

ret = session.query(User).filter(~User.id.in_([1,3,4])).all() # ~xxxx.in_([1,3,4]) 查询不等于1,3,4的

ret = session.query(User).filter(User.id.in_(session.query(User.id).filter_by(name='DragonFire'))).all() 子查询

from sqlalchemy import and_, or_

ret = session.query(User).filter(and_(User.id > 3, User.name == 'DragonFire')).all()

ret = session.query(User).filter(or_(User.id < 2, User.name == 'DragonFire')).all()

ret = session.query(User).filter(

or_(

User.id < 2,

and_(User.name == 'eric', User.id > 3),

User.extra != ""

)).all()

# select * from User where id<2 or (name="eric" and id>3) or extra != ""

# 通配符

ret = db_session.query(User).filter(User.name.like('e%')).all()

ret = db_session.query(User).filter(~User.name.like('e%')).all()

# 限制

ret = db_session.query(User)[1:2]

# 排序

ret = db_session.query(User).order_by(User.name.desc()).all()

ret = db_session.query(User).order_by(User.name.desc(), User.id.asc()).all()

# 分组

from sqlalchemy.sql import func

ret = db_session.query(User).group_by(User.extra).all()

ret = db_session.query(

func.max(User.id),

func.sum(User.id),

func.min(User.id)).group_by(User.name).all()

ret = db_session.query(

func.max(User.id),

func.sum(User.id),

func.min(User.id)).group_by(User.name).having(func.min(User.id) >2).all()"""

#关闭连接

db_session.close()

orm_select_more