mybatis-plus左连接
时间: 2023-09-23 11:12:33 浏览: 48
MyBatis-Plus is a widely used Java persistence framework that extends the capabilities of MyBatis. It provides additional features and utilities to simplify database operations. To perform a left join using MyBatis-Plus, you can use the `leftJoin()` method provided by the `QueryWrapper` class.
Here's an example of how to perform a left join using MyBatis-Plus:
```java
// Assuming you have two entities: User and Order
// Create a QueryWrapper object for the User entity
QueryWrapper<User> queryWrapper = new QueryWrapper<>();
// Perform a left join with the Order entity using the column names for the join condition
queryWrapper.leftJoin("order", "user.id = order.user_id");
// Execute the query
List<User> userList = userMapper.selectList(queryWrapper);
```
In this example, `user` and `order` are the table names, `user.id` and `order.user_id` are the column names used for the join condition. The `selectList()` method will return a list of `User` objects containing the joined data.
Please note that this is just a basic example, and the actual implementation may vary depending on your database schema and mapping configurations.