Mybatis中使用in()查询的方式详解

<select id="studentList" resultType="com.ywt.springboot.model.Student">
        select *
        from student
        where id in
        <foreach collection="array" index="index" item="item" open="(" separator="," close=")">
            #{item}
        </foreach>
    </select>

<select id="studentList" resultType="com.ywt.springboot.model.Student">
        select *
        from student
        where id in
        <foreach collection="list" index="index" item="item" open="(" separator="," close=")">
            #{item}
        </foreach>
    </select>

@Test
    void Test(){
        QueryWrapper<Student> qw = new QueryWrapper<>();
        qw.in("id",7,9);
        List<Student> students = studentMapper.selectList(qw);
        System.out.println(students.toString());
    }

// SQL语句：select * from user where id = ?
// 使用条件构造器QueryWrapper
    @Test
    void queryWrapper(){
        QueryWrapper<User> qw = new QueryWrapper<>();
        qw.eq("id",1);
        List<User> users = userMapper.selectList(qw);
        users.forEach(System.out::print);
    }

// 我们要查询name里姓氏包含 ‘张'，并且年龄小于30岁的
// SQL语句：select * from user where name like '张%' and age < 30
 
// 条件构造器：
    @Test
    void queryWrapper(){
        QueryWrapper<User> qw = new QueryWrapper<>();
        qw.likeRight("name","张").lt("age","30");
        List<User> users = userMapper.selectList(qw);
        users.forEach(System.out::println);
    }

// 查询出年龄在15-25之间，并且他的名字不为空
// SQL语句：select * from user where name is not null and age between(15,25)
 
//条件构造器
    @Test
    void queryWrapper(){
        QueryWrapper<User> qw = new QueryWrapper<>();
        qw.isNotNull("name").between("age",18,25);
        List<User> users = userMapper.selectList(qw);
        users.forEach(System.out::println);
    }

// 查询名字中带有王的，并且年龄不小于30，邮箱为空的
// SQL语句：select * from user where name like '%王%' and age >= 30 and email is null
 
// 条件构造器:
    @Test
    void queryWrapper(){
        QueryWrapper<User> qw = new QueryWrapper<>();
        qw.like("name","王").ge("age",30).isNull("email");
        List<User> users = userMapper.selectList(qw);
        users.forEach(System.out::println);
    }