python下SQlite数据库练习实例 1.创建⼀个学⽣成绩表 Grades， 学号 姓名 成绩 名次 2.往表中插⼊10数据 3.查询成绩⼤于60分的⼈的名字 4.查询成绩⼩于60分的⼈的个数 5.把成绩⼩于60分的⼈的成绩修改为60分 6.删除所有学号⼩于100的⼈的信息 7.查询姓“张”的⼈的所有信息 8.查询所有⼈的成绩，按照成绩从⾼到低排列 9.查询所有⼈的成绩，按照名次从⼩到⼤排列

以下是Python下SQLite数据库练习实例的代码：

import sqlite3

# 连接到数据库
conn = sqlite3.connect('test.db')

# 创建一个学生成绩表 Grades
conn.execute('''CREATE TABLE Grades
             (ID INT PRIMARY KEY NOT NULL,
             NAME TEXT NOT NULL,
             SCORE INT NOT NULL,
             RANK INT NOT NULL);''')

# 往表中插入10个数据
data = [(1, '张三', 80, 1), (2, '李四', 90, 2), (3, '王五', 70, 3), 
        (4, '赵六', 60, 4), (5, '小七', 50, 5), (6, '小八', 40, 6), 
        (7, '小九', 30, 7), (8, '小十', 20, 8), (9, '小十一', 10, 9), 
        (10, '小十二', 0, 10)]

for row in data:
    conn.execute("INSERT INTO Grades (ID, NAME, SCORE, RANK) \
                 VALUES (?, ?, ?, ?)", row)
conn.commit()

# 查询成绩大于60分的人的名字
cursor = conn.execute("SELECT NAME FROM Grades WHERE SCORE > 60")
for row in cursor:
    print("Name = ", row[0])

# 查询成绩小于60分的人的个数
cursor = conn.execute("SELECT COUNT(*) FROM Grades WHERE SCORE < 60")
for row in cursor:
    print("Count = ", row[0])

# 把成绩小于60分的人的成绩修改为60分
conn.execute("UPDATE Grades SET SCORE = 60 WHERE SCORE < 60")
conn.commit()

# 删除所有学号小于100的人的信息
conn.execute("DELETE FROM Grades WHERE ID < 100")
conn.commit()

# 查询姓“张”的人的所有信息
cursor = conn.execute("SELECT * FROM Grades WHERE NAME LIKE '张%'")
for row in cursor:
    print("ID = ", row[0])
    print("Name = ", row[1])
    print("Score = ", row[2])
    print("Rank = ", row[3])

# 查询所有人的成绩，按照成绩从高到低排列
cursor = conn.execute("SELECT * FROM Grades ORDER BY SCORE DESC")
for row in cursor:
    print("ID = ", row[0])
    print("Name = ", row[1])
    print("Score = ", row[2])
    print("Rank = ", row[3])

# 查询所有人的成绩，按照名次从小到大排列
cursor = conn.execute("SELECT * FROM Grades ORDER BY RANK")
for row in cursor:
    print("ID = ", row[0])
    print("Name = ", row[1])
    print("Score = ", row[2])
    print("Rank = ", row[3])

# 关闭数据库连接
conn.close()

注意，在运行这个代码之前，需要确保你已经安装了SQLite数据库。