Advanced Query Examples with MyBatis-Plus: Case Studies and Code Walkthrough

This article presents a series of MyBatis-Plus advanced query case studies, including setup instructions, sample data, and three specific query scenarios.

Scenario 1 demonstrates selecting users whose name contains “Ja” and age is less than 30 using like and lt conditions.

/**
 * 描述：例2.1 查询名字中包含“Ja”并且年龄小于30的用户
 * 作者：博客园-悟空聊架构
 * 时间：2019-01-20
 * Github：https://github.com/Jackson0714/study-mybatis-plus.git
 * 博客园：https://www.cnblogs.com/jackson0714
 */
@Test
public void testSelectByQueryWrapper() {
    System.out.println("----- 查询名字中包含“Ja”并且年龄小于30的用户------");
    QueryWrapper<User> queryWrapper = new QueryWrapper<>();
    queryWrapper.like("name", "ja").lt("age", 30);
    List<User> userList = userMapper.selectList(queryWrapper);
    userList.forEach(System.out::println);
}

Scenario 2 uses like, between, and isNotNull to find users whose name contains “a”, age between 15 and 25, and non‑null email.

/**
 * 描述：例1.2 查询名字中包含“a”并且年龄大于等于15且年龄小于等于35，且email不为空
 * 作者：博客园-悟空聊架构
 * 时间：2019-01-20
 * Github：https://github.com/Jackson0714/study-mybatis-plus.git
 * 博客园：https://www.cnblogs.com/jackson0714
 */
@Test
public void testSelectByQueryWrapper2() {
    System.out.println("----- 查询名字中包含“a”并且年龄大于等于15且年龄小于等于25，且email不为空------");
    QueryWrapper<User> queryWrapper = new QueryWrapper<>();
    //queryWrapper.like("name", "a").ge("age", 15).le("age", 25).isNotNull("email");
    queryWrapper.like("name", "a").between("age", 15, 25).isNotNull("email");
    List<User> userList = userMapper.selectList(queryWrapper);
    userList.forEach(System.out::println);
}

Scenario 3 illustrates using likeRight, or, gt, and ordering by age descending then id ascending to retrieve users whose name starts with “J” and age greater than 26.

/**
 * 描述：例1.3 查询名字中“J”开头并且年龄大于26，按照年龄降序排列，年龄相同按照id升序排列
 * 作者：博客园-悟空聊架构
 * 时间：2019-01-20
 * Github：https://github.com/Jackson0714/study-mybatis-plus.git
 * 博客园：https://www.cnblogs.com/jackson0714
 */
@Test
public void testSelectByQueryWrapper3() {
    System.out.println("----- 查询名字中包含“a”并且年龄大于26，按照年龄降序排列，年龄相同按照id升序排列 ------");
    QueryWrapper<User> queryWrapper = new QueryWrapper<>();
    queryWrapper.likeRight("name","J").or().gt("age",26).orderByDesc("age")
        .orderByAsc("id");
    List<User> userList = userMapper.selectList(queryWrapper);
    userList.forEach(System.out::println);
}

The article also provides a link to the GitHub repository for downloading the full example code and encourages readers to follow the “悟空聊架构” public account for more architecture resources.