然后,我们可以通过 LambdaQueryWrapper 的lambda方法来创建一个查询构造器,并指定要查询的字段: LambdaQueryWrapper<User>queryWrapper=Wrappers.lambdaQuery();queryWrapper.select(User::getAge); 1. 2. 接下来,我们可以通过max方法来进行最大值的聚合操作: IntegermaxAge=userMapper.selectOne(queryWrapper).getAge(); ...
LambdaQueryWrapper<User> queryWrapper = Wrappers.<User>lambdaQuery();if (StringUtils.isNotBlank(username)) {queryWrapper.like(User::getUsername, username);}if (minAge != null) {queryWrapper.ge(User::getAge, minAge);}if (maxAge != null) {queryWrapper.le(User::getAge, maxAge);}List<User>...
在服务层中,我们可以使用 Lambda Query Wrapper 来执行值在区间内的查询。以下是实现的示例方法: importcom.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;importorg.springframework.beans.factory.annotation.Autowired;importorg.springframework.stereotype.Service;importjava.math.BigDecimal;importjava.util...
publicvoidselectByWrapper(){ // 创建queryWrapper的两种方式 QueryWrapper<User> queryWrapper =newQueryWrapper<>(); // QueryWrapper<User> queryWrapper1 = Wrappers.<User>query(); queryWrapper.like("name","刘").gt("age",20); List<User> list = userMapper.selectList(queryWrapper); ...
LambdaQueryWrapper<UserAggr> wrapper = Wrappers.lambdaQuery(UserAggr.class) .select(UserAggr::getDeptId, UserAggr::getCount) .groupBy(UserAggr::getDeptId); List<UserAggr> userAggrList = userAggrMapper.selectList(wrapper); List<UserAggrVo> userAggrVoList = EntityUtils.toList(userAggrList, UserAg...
publicList<UserAggrVo>selectList3(){LambdaQueryWrapper<UserAggr>wrapper=Wrappers.lambdaQuery(UserAggr.class).select(UserAggr::getDeptId,UserAggr::getCount).groupBy(UserAggr::getDeptId);List<UserAggr>userAggrList=userAggrMapper.selectList(wrapper);List<UserAggrVo>userAggrVoList=EntityUtils.toList(user...
publicList<UserAggrVo>selectList3(){LambdaQueryWrapper<UserAggr>wrapper=Wrappers.lambdaQuery(UserAggr.class).select(UserAggr::getDeptId,UserAggr::getCount).groupBy(UserAggr::getDeptId);List<UserAggr>userAggrList=userAggrMapper.selectList(wrapper);List<UserAggrVo>userAggrVoList=EntityUtils.toList(user...
publicList<UserAggrVo>selectList3(){LambdaQueryWrapper<UserAggr>wrapper=Wrappers.lambdaQuery(UserAggr.class).select(UserAggr::getDeptId,UserAggr::getCount).groupBy(UserAggr::getDeptId);List<UserAggr>userAggrList=userAggrMapper.selectList(wrapper);List<UserAggrVo>userAggrVoList=EntityUtils.toList(user...
LambdaQueryWrapper wrapper = new QueryWrapper().lambda(); wrapper.eq(MpSmsBlackList::getPhoneNo, phoneNo); 这么写查询的话,这个条件构造器还没有传到select里面,就报错了,提示: nested exception is org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.builder.BuilderException:...
MybatisPlus Lambda表达式 聚合查询 分组查询 COUNT SUM AVG MIN MAX (五)MybatisPlus代码生成器 只要你想偷懒,那么Java代码生成器便是偷懒的利器,Java代码生成器以MybatisPlus为基础,通过在全局yml文件中复用数据库,读取数据库元数据信息,一件生成domain、mapper、service、controller等Spring MVC风格代码,以单表查询...