为简化开发工作、提高生产率而生
对 MyBatis-Plus 多表查询的扩展 | 演示工程 | 使用文档 | 点个Star支持一下吧 (☆▽☆)
- Maven
<dependency> <groupId>com.github.yulichang</groupId> <artifactId>mybatis-plus-join-boot-starter</artifactId> <version>1.5.5</version> </dependency>
- Gradle 或者clone代码到本地执行
implementation 'com.github.yulichang:mybatis-plus-join-boot-starter:1.5.5'mvn install, 再引入以上依赖
注意: MyBatis Plus版本需要3.1.2+
- mapper继承MPJBaseMapper
class test { @Resource private UserMapper userMapper; void testJoin() { //和Mybatis plus一致，MPJLambdaWrapper的泛型必须是主表的泛型，并且要用主表的Mapper来调用 MPJLambdaWrapper<UserDO> wrapper = JoinWrappers.lambda(UserDO.class) .selectAll(UserDO.class)//查询user表全部字段 .select(UserAddressDO::getTel)//查询user_address tel 字段 .selectAs(UserAddressDO::getAddress, UserDTO::getUserAddress)//别名 .select(AreaDO::getProvince, AreaDO::getCity) .leftJoin(UserAddressDO.class, UserAddressDO::getUserId, UserDO::getId) .leftJoin(AreaDO.class, AreaDO::getId, UserAddressDO::getAreaId) .eq(UserDO::getId, 1) .like(UserAddressDO::getTel, "1") .gt(UserDO::getId, 5); //连表查询 返回自定义ResultType List<UserDTO> list = userMapper.selectJoinList(UserDTO.class, wrapper); //分页查询 （需要启用 mybatis plus 分页插件） Page<UserDTO> listPage = userMapper.selectJoinPage(new Page<>(2, 10), UserDTO.class, wrapper); } }对应sql
SELECT t.id, t.name, t.sex, t.head_img, t1.tel, t1.address AS userAddress, t2.province, t2.city FROM user t LEFT JOIN user_address t1 ON t1.user_id = t.id LEFT JOIN area t2 ON t2.id = t1.area_id WHERE ( t.id = ? AND t1.tel LIKE ? AND t.id > ?) 
![@dependabot[bot]](https://avatars.githubusercontent.com/in/29110?s=64&v=4){kind=small}
