mybatisplus wrapper 清空表

对于MybatisPlus的Wrapper，如果想要清空表，可以使用如下方式：

Wrapper wrapper = new Wrapper() {
    @Override
    public String getSqlSegment() {
        return "truncate table table_name";
    }
};
myMapper.delete(wrapper);

其中，`truncate table table_name`是清空表的SQL语句，通过Wrapper传递给MybatisPlus的delete方法，可以实现清空表的功能。

相关问题

mybatisplus wrapper多表分页查询

Mybatis-Plus提供了一种方便的方式来实现多表分页查询，使用Wrapper对象可以很容易地实现多表关联查询和分页功能。

首先，在Mapper接口中定义一个方法，方法参数中使用Page对象和Wrapper对象：

List<User> selectUserPage(Page<User> page, @Param("wrapper") Wrapper<User> wrapper);

然后，在Mapper.xml文件中实现该方法，使用多表关联查询和分页功能：

<select id="selectUserPage" resultType="User">
    SELECT *
    FROM user u
    <where>
        <if test="wrapper != null">
            ${wrapper.sqlSegment}
        </if>
    </where>
    <if test="page != null">
        LIMIT #{page.offset}, #{page.size}
    </if>
</select>

在调用该方法时，可以使用LambdaQueryWrapper对象来构建条件查询：

Page<User> page = new Page<>(1, 10);
LambdaQueryWrapper<User> wrapper = new LambdaQueryWrapper<>();
wrapper.eq(User::getUsername, "admin")
        .or()
        .eq(User::getUsername, "root");
List<User> userList = userMapper.selectUserPage(page, wrapper);

这样就可以实现多表关联查询和分页功能了。需要注意的是，如果没有使用Wrapper对象，则查询结果将为全表数据，不会进行分页。

mybatisplus wrapper orand

MyBatis-Plus (also known as MyBatis+) is an enhanced version of the MyBatis framework. It provides additional features and utilities to simplify the development process.

The `Wrapper` class in MyBatis-Plus is used to construct SQL queries dynamically. It provides a set of methods that can be used to add conditions to the query. For example, `eq` adds an equal condition, `like` adds a like condition, and so on. `Wrapper` also supports nested queries and complex conditions.

`or` and `and` are two methods provided by the `Wrapper` class to specify how the conditions should be combined. `and` is used to add conditions that must all be true, while `or` is used to add conditions where at least one must be true.

In summary, `Wrapper` is a powerful tool for constructing dynamic SQL queries in MyBatis-Plus, and `or` and `and` are two methods that can be used to combine conditions in the query.