https://blog.csdn.net/weixin_41463944/article/details/126453544?spm=1001.2014.3001.5501
2、测试代码
package com.example.springbootmybatisplus;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.example.springbootmybatisplus.mapper.UserMapper;
import com.example.springbootmybatisplus.pojo.User;
import com.example.springbootmybatisplus.pojo.UserscoreMap;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBoottest;
import java.util.List;
import java.util.Map;
@SpringBoottest
public class WrapperTest {
@Autowired
private UserMapper userMapper;
//入门
@Test
void contextLoads() {
//查询name不为空的用户,并且邮箱不为空的用户,并且年龄大于等于12岁的
QueryWrapper<User> wrapper = new QueryWrapper<>();
wrapper
.isNotNull("name")
.isNotNull("email")
.ge("age",40);
List<User> users = userMapper.selectList(wrapper);
System.out.println(users);
}
@Test
void test2(){
//查询名字等于第四十
QueryWrapper<User> wrapper = new QueryWrapper<>();
// wrapper.ge("id",8);
// wrapper.le("id",13);
List<User> users = userMapper.selectList(wrapper);
//User user = userMapper.selectOne(wrapper);
System.out.println(users);
}
@Test
void test3(){
//查询用户年龄在20-30之间的
QueryWrapper<User> wrapper = new QueryWrapper<>();
wrapper.between("age",20,30);
Integer count = userMapper.selectCount(wrapper);
System.out.println("数量");
System.out.println(count);
}
//模糊查询
@Test
void test4(){
//名字中不包含四十的
QueryWrapper<User> wrapper = new QueryWrapper<>();
//左和右 %e e%
wrapper
.notLike("name","四十")
.likeRight("email","t");
List<Map<String, Object>> maps = userMapper.selectMaps(wrapper);
System.out.println(maps);
}
@Test
void test5(){
//id在子查询中查出来
QueryWrapper<User> wrapper = new QueryWrapper<>();
wrapper.insql("id","select id from user where id < 5");
List<Object> objects = userMapper.selectObjs(wrapper);
System.out.println(objects);
}
@Test
void test6(){
//排序 id降序
QueryWrapper<User> wrapper = new QueryWrapper<>();
wrapper.orderByDesc("id");
List<User> users = userMapper.selectList(wrapper);
System.out.println(users);
}
@Test
void test7(){
List<UserscoreMap> result=userMapper.userscoreList();
System.out.println("联查结果");
System.out.println(result);
}
}
3、整理笔记位置
原文地址:https://www.jb51.cc/wenti/3287292.html
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