MybatisPlus使用Mybatis的XML的动态SQL的功能实现多表查询

<dependencies>
   <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
    </dependency>

    <dependency>
        <groupId>com.baomidou</groupId>
        <artifactId>mybatis-plus-boot-starter</artifactId>
        <version>3.5.2</version>
    </dependency>

    <dependency>
        <groupId>net.coobird</groupId>
        <artifactId>thumbnailator</artifactId>
        <version>0.4.19</version>
    </dependency>

    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
</dependencies>

#DataSource Config
spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    username: root
    password: 123456
    url: jdbc:mysql://localhost:3306/WMSPlus?useUnicode=true&useSSL=false&characterEncoding=utf8
  servlet:
    multipart:
      enabled: true #是否启用http上传处理
      max-request-size: 100MB #最大请求文件的大小
      max-file-size: 20MB #设置单个文件最大长度
	  file-size-threshold: 20MB #当文件达到多少时进行磁盘写入

#mybatis-plus
mybatis-plus:
  configuration:
    map-underscore-to-camel-case: false # 数据库下划线自动转驼峰标示关闭
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
  mapper-locations: classpath:/mapper/*.xml

#主机的端口资源
localhost: http://192.168.123.146:9090

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
        <!--这里面的namespace要对应好对应的BaseMapper的类路径-->
<mapper namespace="com.mapper.UserMapper">

	<!--这里的id名字是对应方法名字-->
    <select id="getAllUser" resultType="com.entity.User">
        select * from user
    </select>

</mapper>

package com.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.entity.User;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Select;

import java.util.List;

/**
 * @author：DUOLUONIANDAI
 * @DATA：2023/3/29 13:45
 * @Title：user的mapper
 */
@Mapper
public interface UserMapper extends BaseMapper<User> {
	//这里的getAllUser要对应好XML里面的id名字
    public List<User> getAllUser();
}