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=newLambdaQueryWrapper<>();queryWrapper.select(User::getAge).orderByDesc(User::getAge).last("LIMIT 1");UsermaxUser=userService.getOne(queryWrapper);System.out.println("The maximum age is: "+maxUser.getAge()); 1. 2. 3. 4. 5. 6. 7. In this code sn...
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>...
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...
LambdaQueryWrapper wrapper = new QueryWrapper().lambda(); wrapper.eq(MpSmsBlackList::getPhoneNo, phoneNo); 2、打包环境是jdk1.8.0_191、运行环境是Linux 的jdk1.8.0_12 3、启动程序,访问接口,执行到这个条件构造器的时候就报错 报错信息 nested exception is org.mybatis.spring.MyBatisSystemException: ne...
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...
I've been developing a large library of LAMBDA functions and I found myself in need of some crude performance testing, as many of my functions return large arrays and can take some time to execute. I've seen many solutions using Evaluate() in VBA, but I eventually realized I could do ...