flask sql查询

以下是使用Flask进行SQL查询的示例代码：

from flask import Flask
from flask_sqlalchemy import SQLAlchemy

app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'mysql://username:password@localhost/db_name'
db = SQLAlchemy(app)

class Student(db.Model):
    __tablename__ = 'student'
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(50))
    gender = db.Column(db.String(10))
    age = db.Column(db.Integer)
    classes = db.Column(db.String(50))
    cls_id = db.Column(db.Integer, db.ForeignKey('grades.id'))

class Grades(db.Model):
    __tablename__ = 'grades'
    id = db.Column(db.Integer, primary_key=True)
    grade = db.Column(db.String(50))

# 查询所有学生的班级
query1 = db.session.query(Student.classes).distinct().all()
print(query1)

# 按用户名模糊查询学生信息和成绩
query2 = db.session.query(Student.id, Student.name, Student.gender, Student.age, Student.classes, Grades.grade).join(Grades, Student.cls_id == Grades.id).filter(Student.name.like('%李%'))
print(query2)
print(query2.all())