文章目錄

• • 1 增
  • 2 刪
  • 3 改
  • 4 基礎查詢
  • • 4.1 基礎查詢匯總
    • 4.2 限制查詢
    • 4.3 計數
    • 4.4 去重
    • 4.5 排序
    • 4.6 模糊查詢
    • 4.7 分組查詢
    • 4.8 聚合函數
  • 5 多表查詢
  • • 5.1 內連接
    • 5.2 左外連接
    • 5.3 復雜查詢
    • 5.4 三表連接
    • 5.5 利用SQLAlchemy執行原生SQL
  • 6 原生語句查詢 返回json格式
  • 3 統計數量

1 增

Customer為表名

try:username = '123456'customerInfo = Customer(username=username)db.add(customerInfo) # 添加數據db.commit() # 提交即保存到數據庫 except Exception as e:db.rollback()print(e)

2 刪

# 刪除 @route('/professionDeleteType/<num>') def professionDeleteType(db,num):print(num)try:print('--------刪除--------------')print(num)TypeNameInfo = db.query(Profession).filter(Profession.pid==int(num)).delete()db.commit() # 提交即保存到數據庫# db.close() # 關閉會話except Exception as e:print(e)return redirect('/profession')

3 改

Users表

try:username = db.query(Users).filter_by(username=username).first()username.nickname = Hnicknameusername.img_url = Himg_urldb.commit() except:db.rollback()print(e)return json.dumps({'data': 0, 'info': '內部錯誤，請刷新！！！'})

4 基礎查詢

4.1 基礎查詢匯總

# select * from users; result = db.query(Users).all() # select uid, username from users; result = db.query(Users.uid, Users.username).all() # select * from users where uid=17 and username='666'; result = db.query(Users).filter_by(uid=17, username='666').all() # select * from users where uid>=16 or username='666'; result = db.query(Users).filter(or_(Users.uid >= 16,Users.username == '666' )).all()

4.2 限制查詢

# 查詢前3行 result = db.query(Users).limit(3).all() # select * from users limit 3,5; result = db.query(Users).limit(3).offset(3).all()

limit：查詢多少條
offset：偏移量 -> 3 表示從第4條開始

4.3 計數

select count(*) from users where ...

filter：== >= < > != != in not

count = db.query(Users).filter(Users.uid > 16).count() print(count)

4.4 去重

select distinct(openid) from users; result = db.query(Users.openid).distinct(Users.openid).all() print(result) for row in result:print(row.openid)

4.5 排序

select * from users order by uid desc; result = db.query(Users).order_by(Users.uid.desc()).all()

4.6 模糊查詢

select * from users where username like '%929%'; result = db.query(Users).filter(Users.username.like('%929%')).all()

4.7 分組查詢

select * from users group by isAdmin; result = db.query(Users).group_by(Users.openid).all() result = db.query(Users).group_by(Users.openid).having(Users.uid > 2).all()

4.8 聚合函數

min、max、avg、sum

select sum(u_dealNum) from users; result = db.query(func.sum(Users.u_dealNum)).first() print(result)

5 多表查詢

5.1 內連接

查詢發表過文章的 用戶信息+文章信息

select a_title from users, article where users.uid=article.uid and article.a_id=1; select a_title from article inner join users on users.uid=article.uid where article.a_id=1; # 多表查詢時，返回的結果集不再是單純的[Model, Model]數據結構，而是每張表的結果有獨立的對象來維護 result = db.query(Article, Users).join(Users, Article.uid == Users.uid).filter(Article.a_id == 1).all() print(result) for article, users in result:print(article.uid, article.a_title, users.username) result = db.query(Article, Users.username).join(Users, Article.uid == Users.uid).filter(Article.a_id == 1).all() print(result) for article, username in result:print(article.uid, article.a_title, username)

5.2 左外連接

查詢所有用戶 寫的文章閱讀量

select nickname,a_title,sum(a_pageviews) as total from users left join article on users.uid=article.uid group by users.uid having total>0; result = db.query(Users.uid, Users.nickname, func.sum(Article.a_pageviews)).outerjoin(Article, Users.uid == Article.uid).group_by(Users.uid).all()

5.3 復雜查詢

and和or混用: username like 'charles' or uid>1 and nickname='導演'

result = db.query(Users).filter(or_(Users.username.like('charles'), and_(Users.uid > 1, Users.nickname == "導演"))).all() result = db.query(Users).filter(Users.username.like('charles'), or_(Users.uid > 1, Users.nickname == "導演")).all() print(result) for row in result:print(row.uid, row.username)

5.4 三表連接

result = db.query(Article, Users).join(Users, Article.uid == Users.uid) \.join(Label, Article.l_id == Label.l_id).all()

5.5 利用SQLAlchemy執行原生SQL

result = db.execute("select * from users").fetchall() print(result)

6 原生語句查詢 返回json格式

try:sql = ''Info = db.execute(sql)print(Info) except Exception as e:db.rollback()print(e) results = [] for i in searchs:bid = i['bid'] # 索引isbn = i['isbn'] # isbnprint(bid)print(isbn)result = {"bid": bid,"isbn": isbn,}print(result)results.append(result)data = {"status": '1',"results": results } return json.dumps(data)

3 統計數量

from sqlalchemy import func older_num = db.query(func.count(Order_history.seller)).filter_by(seller=uname).scalar()

Sqlchemy查詢結果轉json
MySQL 查詢統計 日期查詢

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