mybatis-plus-join

MyBatis-Plus is an enhanced version of MyBatis, a popular Java-based persistence framework. MyBatis-Plus provides additional features and functionalities, including support for join queries.

To perform join queries using MyBatis-Plus, you can use the `join` method provided by the `QueryWrapper` class. This method allows you to specify the join type, table name, and join condition.

Here's an example of how to perform an inner join using MyBatis-Plus:

QueryWrapper<User> queryWrapper = new QueryWrapper<>();
queryWrapper.eq("user_id", 1)
    .join("order", "user.user_id = order.user_id")
    .select("user.*", "order.order_no");

List<User> userList = userMapper.selectList(queryWrapper);

In this example, we are querying for a user with `user_id` equal to 1 and joining the `order` table using the `user_id` column as the join condition. We are also selecting all columns from the `user` table and the `order_no` column from the `order` table.

MyBatis-Plus supports other types of joins, including left join, right join, and full outer join. You can specify the join type using the `JoinType` enumeration provided by MyBatis-Plus.

Overall, MyBatis-Plus makes it easy to perform join queries in Java applications using the MyBatis framework.