# 54 filter方法常用过滤条件 过滤是数据库的一个很重要的功能，以下对一些常用的过滤条件进行解释，并且这些过滤条件都是只能通过filter方法实现的 如果想看底层sql原生语句，在语句末尾不加all\(\)，就可以打印出原生sql语句 1.equals ```text article = session.query(Article).filter(Article.id == 1).first() print(article) ``` 2.not equals ```text article = session.query(Article).filter(Article.title != 'title0').all() print(article) ``` 3.like & ilike\(不区分大小写\) ```text rticles = session.query(Article).filter(Article.title.like('%title%')).all() # 不分区大小写 articles = session.query(Article).filter(Article.title.ilike('%title%')).all() print(articles) ``` 4.in ```text articles = session.query(Article).filter(Article.title.in_(['title1','title2'])).all() print(articles) ``` 5.not in ```text icles = session.query(Article).filter(~Article.title.in_(['title1'])).all() # articles = session.query(Article).filter(Article.title.notin_(['title1'])).all() print(articles) ``` 6.is null ```text session.query(Article).filter(Article.content == None).all() print(articles) ``` 7.is not null ```text articles = session.query(Article).filter(Article.content != None).all() print(articles) ``` 8.or ```text articles = session.query(Article).filter(or_(Article.title=='title0',Article.content=='123')).all() print(articles) ``` 9.and ```text rticles = session.query(Article).filter(Article.title=='title0' and Article.content == '123').all() articles = session.query(Article).filter(and_(Article.title=='title0',Article.content == '123')).all() print(articles) ``` ```text from sqlalchemy import create_engine, Column, Integer, Text, String, DateTime, String, Float, func,and_,or_ from sqlalchemy.ext.declarative import declarative_base from sqlalchemy.orm import sessionmaker import random HOSTNAME = '127.0.0.1' PORT = "3306" USERNAME = "root" PASSWORD = "123456" DATABASE = "xt_flask" DB_URI = "mysql+pymysql://{}:{}@{}:{}/{}?charset=utf8".format(USERNAME,PASSWORD,HOSTNAME,PORT,DATABASE) from datetime import datetime engine = create_engine(DB_URI) Base = declarative_base(engine) session = sessionmaker(engine)() class Article(Base): __tablename__ = "article" id = Column(Integer,primary_key=True,autoincrement=True) title = Column(String(50),nullable=False) price = Column(Float,nullable=False) content = Column(Text) def __repr__(self): return "<Article(title:%s)>" % self.title # session.query(Article).filter(Article.id) # 筛选关键字 # session.query(Article).filter_by(id=1) # 1.equal # article = session.query(Article).filter(Article.id == 1).first() # print(article) # # 2.not equal # article = session.query(Article).filter(Article.title != 'title0').all() # print(article) # # 3. like # articles = session.query(Article).filter(Article.title.like('%title%')).all() # # 不分区大小写 # articles = session.query(Article).filter(Article.title.ilike('%title%')).all() # print(articles) # # 4. in # articles = session.query(Article).filter(Article.title.in_(['title1','title2'])).all() # print(articles) # # 5. not in & ~ # articles = session.query(Article).filter(~Article.title.in_(['title1'])).all() # # articles = session.query(Article).filter(Article.title.notin_(['title1'])).all() # print(articles) # # 6. is null # articles = session.query(Article).filter(Article.content == None).all() # print(articles) # # 7. is not null # articles = session.query(Article).filter(Article.content != None).all() # print(articles) # # 8. and # # articles = session.query(Article).filter(Article.title=='title0' and Article.content == '123').all() # articles = session.query(Article).filter(and_(Article.title=='title0',Article.content == '123')).all() # print(articles) # 9. or articles = session.query(Article).filter(or_(Article.title=='title0',Article.content=='123')).all() print(articles) ```