mybatis-plus and使用

Mybatis-Plus是一个基于Mybatis的增强工具，它简化了Mybatis的开发流程，提供了许多实用的功能，如自动生成代码、分页查询、条件构造器等。使用Mybatis-Plus可以大大提高开发效率，减少重复代码的编写。

相关问题

mybatis-plusand和or

MyBatis-Plus is an open-source persistence framework for Java applications. It is an extension to the MyBatis framework, providing additional features and functionalities to simplify database operations.

When it comes to combining conditions in MyBatis-Plus, you can use both "and" and "or" operators to construct complex queries. Here's how you can use them:

1. Using "and" operator:
You can use the `and` method to add multiple conditions together, which means all conditions must be true for a record to be included in the result. Here's an example:

   QueryWrapper<Entity> queryWrapper = new QueryWrapper<>();
   queryWrapper.eq("column1", value1)
               .and(wrapper -> wrapper.eq("column2", value2)
                                    .ne("column3", value3));

2. Using "or" operator:
You can use the `or` method to add multiple conditions together, which means any of the conditions can be true for a record to be included in the result. Here's an example:

   QueryWrapper<Entity> queryWrapper = new QueryWrapper<>();
   queryWrapper.eq("column1", value1)
               .or(wrapper -> wrapper.eq("column2", value2)
                                   .ne("column3", value3));

With these operators, you can build complex queries by combining multiple conditions in MyBatis-Plus.

mybatis-plus and和or

MyBatis-Plus是一个基于MyBatis的代码生成器和持久层框架的增强工具，它提供了一种更加便捷的方式来操作数据库，简化了常见的CRUD（创建、读取、更新、删除）操作。在MyBatis-Plus中，"and" 和 "or" 关键字用于构建SQL查询条件中的逻辑连接。

1. **and**: `and` 关键字用于组合多个条件，表示它们之间为“并且”关系。例如，如果你想查找年龄大于20且性别为男的学生，你可以这样写：

   QueryWrapper<Student> wrapper = new QueryWrapper<>();
   wrapper.eq("age", 20).eq("gender", "male");
   List<Student> students = studentService.selectList(wrapper);

2. **or**: `or` 关键字用于组合多个条件，表示它们之间为“或”关系。比如查找名字包含"张"或姓氏为"李"的人：

   QueryWrapper<Student> wrapper = new QueryWrapper<>();
   wrapper.or().like("name", "张%").or().eq("surname", "李");
   List<Student> users = studentService.selectList(wrapper);

在MyBatis-Plus的QueryWrapper API中，这些关键字帮助你动态构建复杂的查询条件，提高了代码的灵活性和可维护性。