--来自CommentMapper.xml文件 --> 2. <resultMap type="Comment" id="CommentResult"> 3. <association property="blog" select="selectBlog" column="blog" javaType="Blog"/> 4. </resultMap> 5. 6. <select id="selectComment" parameterType="int" resultMap="CommentResult"> 7. id 8. </select>...
*条件构造器 查询操作SelectList */ @Test public void testEntitymapperSelectList() { //查询数据库,性别为男(1),并且名字中带有霸的记录或者email中带有123的记录。 List<Employee> employeeList=employeeMapper.selectList(new EntityWrapper<Employee>() .eq("gender",1) .like("name", "霸") //.or()/...
我们先讲这个selectById,selectBatchIds,selectByMap方法,后面讲条件构造器以及分页再讲; @TestpublicvoidselectById(){ Department department= departmentMapper.selectById(1); System.out.println(department); } @TestpublicvoidselectBatchIds(){ List<Integer> idList=newArrayList<>(); idList.add(1); idList.a...
mybatis-plus中selectList用法 SELECT*FROMuser_infoWHEREtom_age='20'andname='tom'; 等同于 QueryWrapper<UserInfo> queryWrapper =newQueryWrapper(); queryWrapper.eq("tom_age", '20');//tom_age必须是数据库中的字段queryWrapper.eq("name",'tom'); List<UserInfo> list = userInfoMapper.selectList(query...
使用BaseMapper接口中的selectList方法,传入参数QueryWrapper,写法2 @RequestMapping("/test5") @ResponseBody public String test5() { List<User> plainUsers2 = userMapper.selectList(new LambdaQueryWrapper<User>() .inSql(User::getRoleId,"select id from role where id = 2")); ...
Mybatis-Plus通用Mapper CRUD之select mybatis-plus框架提供了很多查询方法: /** * 根据 ID 查询 * * @param id 主键ID */ T selectById(Serializable id); /** * 查询(根据ID 批量查询) * * @param idList 主键ID列表(不能为 null 以及 empty)...
userMapper.selectList(queryWrapper).forEach(System.out::println); QueryWrapper<User> queryWrapper8 = new QueryWrapper<>(); Map<String,Object> map2 = new HashMap<>(); map2.put("name","123"); //map.put("age",null); queryWrapper8.allEq(map2); ...
mapper.xml: <select id="countStudent" resultType="int"> select count(*) from student </select> 1. 2. 3. 测试方法: @Test public void testRetunInt(){ int count = studentDao.countStudent(); System.out.println("学生总人数:"+ count); ...
Mybatis plus实现Distinct去重功能 不啰嗦,上菜 QueryWrapperqueryWrapper=newQueryWrapper(); queryWrapper.select("DISTINCT no,name").orderByAsc("no");returnmapper.selectList(queryWrapper);123 PS: 顺便一提,指明查询出后的结果输出类型,可以参考如下:
SELECT id,name,age,email FROM user ORDER BY age ASC 按条件查询,使用BaseMapper的selectList方法,传入参数QueryWrapper,并指定要查询的字段 @RequestMapping(value ="/test12") @ResponseBody public String test12(){ mapper.selectList(new QueryWrapper<User>().select("id","name")) ...