select * from student where sdept in (select sdept from student where sname='刘晨'“刘晨”附近有语法错误。

这个SQL语句的作用是查询学生表中和名为“刘晨”的学生所在系相同的所有学生信息。可能是因为你输入的语句中缺少引号导致出现了语法错误。正确的SQL语句应该是：

select * from student where sdept in (select sdept from student where sname='刘晨')

其中，子查询 `select sdept from student where sname='刘晨'` 用于查询名为“刘晨”的学生所在系的名称，而外层查询则通过 `in` 子句，找到所有与该系名称相同的学生信息。

相关问题

CREATE DATABASE if NOT EXISTS xskc CHARSET UTF8 COLLATE UTF8_GENERAL_CI; use xskc; CREATE TABLE STUDENT ( Sno char(9)primary key, Sname char(20), Ssex char(2)check(Ssex in('男','女')) , Sage smallint check(Sage>=10 and Sage<=60), Sdept char(20) ); insert into STUDENT(Sno,Sname,Ssex,Sage,Sdept)values(201215121,'李勇','男',20,'CS'); insert into STUDENT(Sno,Sname,Ssex,Sage,Sdept)values(201215122,'刘晨','女',19,'IS'); insert into STUDENT(Sno,Sname,Ssex,Sage,Sdept)values(201215123,'王敏','男',18,'MA'); insert into STUDENT(Sno,Sname,Ssex,Sage,Sdept)values(201215124,'张立','男',19,'CS'); select * from STUDENT; CREATE TABLE COURSE ( Cno char(4)primary key, Cname char(40), Cpno char(4), foreign key(Cpno)references COURSE(Cno), Ccredit smallint ); insert into COURSE(Cno,Cname,Cpno,Ccredit)values(1,'数据库',NULL,4); insert into COURSE(Cno,Cname,Cpno,Ccredit)values(2,'数学',NULL,2); insert into COURSE(Cno,Cname,Cpno,Ccredit)values(3,'信息系统',1,4); insert into COURSE(Cno,Cname,Cpno,Ccredit)values(4,'操作系统',2,3); insert into COURSE(Cno,Cname,Cpno,Ccredit)values(5,'数据结构',3,4); insert into COURSE(Cno,Cname,Cpno,Ccredit)values(6,'数据分析',NULL,4); insert into COURSE(Cno,Cname,Cpno,Ccredit)values(7,'PASCAL语言',6,4); select * from COURSE; CREATE TABLE SC ( Sno char(9), Cno char(4), Grade smallint check(Grade>=10 and Grade<=100), primary key(Sno,Cno), foreign key(Sno) references STUDENT(Sno), foreign key(Cno) references COURSE(Cno) ); insert into SC(Sno,Cno,Grade)values(201215121,1,92); insert into SC(Sno,Cno,Grade)values(201215121,2,85); insert into SC(Sno,Cno,Grade)values(201215121,3,88); insert into SC(Sno,Cno,Grade)values(201215122,2,90); insert into SC(Sno,Cno,Grade)values(201215122,3,80);

好的，我看到您创建了三张表：`STUDENT`、`COURSE` 和 `SC`，并向它们插入了一些数据。表 `STUDENT` 存储了学生的基本信息，表 `COURSE` 存储了课程的信息，表 `SC` 存储了学生选课的成绩信息。接下来，您可以使用 SQL 语句来查询学生的成绩信息，如下：

1. 查询学生 `201215121` 的选课情况和成绩：

SELECT c.Cname, sc.Grade
FROM SC sc
JOIN COURSE c ON sc.Cno = c.Cno
WHERE sc.Sno = 201215121;

执行该 SQL 语句后，将会返回学号为 `201215121` 的学生选课的课程名称和成绩信息。

2. 查询课程 `数据库` 的选课学生情况和成绩：

SELECT s.Sname, sc.Grade
FROM SC sc
JOIN STUDENT s ON sc.Sno = s.Sno
JOIN COURSE c ON sc.Cno = c.Cno
WHERE c.Cname = '数据库';

执行该 SQL 语句后，将会返回选修了 `数据库` 课程的学生的姓名和成绩信息。

3. 查询所有学生的选课情况和成绩：

SELECT s.Sno, s.Sname, c.Cname, sc.Grade
FROM SC sc
JOIN STUDENT s ON sc.Sno = s.Sno
JOIN COURSE c ON sc.Cno = c.Cno;

执行该 SQL 语句后，将会返回所有学生的选课情况和成绩信息。

用Java设计目录结构 建表一下表Sno 201215122 201215123 201215125； Sname 刘晨王敏张立 ；Ssex女女男； Sage 19 18 19 ；Sdept CS MA IS

目录结构：

src/
└── main/
    ├── java/
    │   ├── model/
    │   │   └── Student.java
    │   ├── dao/
    │   │   └── StudentDao.java
    │   └── util/
    │       └── DatabaseUtil.java
    └── resources/
        └── db.properties

建表 SQL：

CREATE TABLE student (
    sno VARCHAR(10) PRIMARY KEY,
    sname VARCHAR(20) NOT NULL,
    ssex VARCHAR(2) NOT NULL,
    sage INT NOT NULL,
    sdept VARCHAR(20) NOT NULL
);

Java 代码：

Student.java

package model;

public class Student {
    private String sno;
    private String sname;
    private String ssex;
    private int sage;
    private String sdept;

    public Student(String sno, String sname, String ssex, int sage, String sdept) {
        this.sno = sno;
        this.sname = sname;
        this.ssex = ssex;
        this.sage = sage;
        this.sdept = sdept;
    }

    public String getSno() {
        return sno;
    }

    public void setSno(String sno) {
        this.sno = sno;
    }

    public String getSname() {
        return sname;
    }

    public void setSname(String sname) {
        this.sname = sname;
    }

    public String getSsex() {
        return ssex;
    }

    public void setSsex(String ssex) {
        this.ssex = ssex;
    }

    public int getSage() {
        return sage;
    }

    public void setSage(int sage) {
        this.sage = sage;
    }

    public String getSdept() {
        return sdept;
    }

    public void setSdept(String sdept) {
        this.sdept = sdept;
    }
}

StudentDao.java

package dao;

import model.Student;

import java.sql.*;
import java.util.ArrayList;
import java.util.List;

public class StudentDao {
    private String url;
    private String username;
    private String password;

    public StudentDao(String url, String username, String password) {
        this.url = url;
        this.username = username;
        this.password = password;
    }

    public List<Student> getAllStudents() {
        List<Student> students = new ArrayList<>();

        try (Connection connection = DriverManager.getConnection(url, username, password);
             Statement statement = connection.createStatement();
             ResultSet resultSet = statement.executeQuery("SELECT * FROM student")) {
            while (resultSet.next()) {
                String sno = resultSet.getString("sno");
                String sname = resultSet.getString("sname");
                String ssex = resultSet.getString("ssex");
                int sage = resultSet.getInt("sage");
                String sdept = resultSet.getString("sdept");

                Student student = new Student(sno, sname, ssex, sage, sdept);
                students.add(student);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }

        return students;
    }

    public boolean addStudent(Student student) {
        try (Connection connection = DriverManager.getConnection(url, username, password);
             PreparedStatement statement = connection.prepareStatement(
                     "INSERT INTO student (sno, sname, ssex, sage, sdept) VALUES (?, ?, ?, ?, ?)")) {
            statement.setString(1, student.getSno());
            statement.setString(2, student.getSname());
            statement.setString(3, student.getSsex());
            statement.setInt(4, student.getSage());
            statement.setString(5, student.getSdept());

            int rows = statement.executeUpdate();
            return rows > 0;
        } catch (SQLException e) {
            e.printStackTrace();
            return false;
        }
    }

    public boolean updateStudent(Student student) {
        try (Connection connection = DriverManager.getConnection(url, username, password);
             PreparedStatement statement = connection.prepareStatement(
                     "UPDATE student SET sname=?, ssex=?, sage=?, sdept=? WHERE sno=?")) {
            statement.setString(1, student.getSname());
            statement.setString(2, student.getSsex());
            statement.setInt(3, student.getSage());
            statement.setString(4, student.getSdept());
            statement.setString(5, student.getSno());

            int rows = statement.executeUpdate();
            return rows > 0;
        } catch (SQLException e) {
            e.printStackTrace();
            return false;
        }
    }

    public boolean deleteStudent(String sno) {
        try (Connection connection = DriverManager.getConnection(url, username, password);
             PreparedStatement statement = connection.prepareStatement("DELETE FROM student WHERE sno=?")) {
            statement.setString(1, sno);

            int rows = statement.executeUpdate();
            return rows > 0;
        } catch (SQLException e) {
            e.printStackTrace();
            return false;
        }
    }
}

DatabaseUtil.java

package util;

import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Properties;

public class DatabaseUtil {
    private static String url;
    private static String username;
    private static String password;

    static {
        try (InputStream inputStream = DatabaseUtil.class.getClassLoader().getResourceAsStream("db.properties")) {
            Properties properties = new Properties();
            properties.load(inputStream);

            url = properties.getProperty("url");
            username = properties.getProperty("username");
            password = properties.getProperty("password");

            Class.forName(properties.getProperty("driver"));
        } catch (IOException | ClassNotFoundException e) {
            e.printStackTrace();
        }
    }

    public static Connection getConnection() throws SQLException {
        return DriverManager.getConnection(url, username, password);
    }
}

db.properties

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/test?useSSL=false
username=root
password=123456