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https://gitee.com/best_handsome/mybatis-plus-join
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57 lines
1.9 KiB
Markdown
57 lines
1.9 KiB
Markdown
# mybatis-plus-join
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支持连表查询的[mybatis-plus](https://gitee.com/baomidou/mybatis-plus)
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## 运行环境
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* mysql8
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* jdk8
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* mybatis-plus 3.4.2
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## 使用方法
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### 使用
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* entity继承MyBaseEntity
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* mapper继承MyBaseMapper
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* service继承MyBaseService
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* serviceImpl继承MyBaseServiceImpl
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### MyLambdaQueryWrapper用法
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#### select(UserEntity::getId) 查询指定的字段,支持可变参数
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查询user表中的head_img,name和user_address表中的address,tel
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对应sql
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#### selectAll(UserEntity.class) 查询UserEntity全部字段
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查询user全部字段和user_address表中的address,tel
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对应sql
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#### as(UserEntity::getHeadImg,UserDTO::getUserHeadImg)
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查询字段head_img as userHeadImg
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对应sql
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#### 左连接 leftJoin(UserEntity::getId,UserAddressEntity::getUserId,right -> right)
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前连个参数是两个表的连接条件:
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user left join user_address on user.id = User_address.user_id
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第三个参数是右表wrapper对象,可以继续使用,以上方法.
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#### 条件查询eq()
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对应sql
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#### [参考测试类](https://gitee.com/best_handsome/mybatis-plus-join/blob/master/src/test/java/com/example/mp/MpJoinTest.java)
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