mybatis-plus的一些骚操作

1.统计本月、上月数据

        
// 上月
long lastMonth =
                new DeviceRepairs()
                        .selectCount(
                                Wrappers.lambdaQuery(DeviceRepairs.class)
                                        .apply(
                                                " PERIOD_DIFF( date_format( now( ), '%Y%m' ), date_format( create_time, '%Y%m' ) ) =1 ")
                                        .last(" limit 1"));

// 本月       
 long currentMonth=
                new FarmCrop()
                        .selectCount(
                                Wrappers.lambdaQuery(FarmCrop.class)
                                        .apply(
                                                " DATE_FORMAT( create_time, '%Y%m' ) = DATE_FORMAT( CURDATE( ) ,'%Y%m' )  ")
                                        .last(" limit 1"));

2.聚合函数

                        DeviceWeatherData maxSpeed =
                                new DeviceWeatherData()
                                        .selectOne(
                                                Wrappers.query(new DeviceWeatherData())
                                                        .select(" max(windSpeed) as windSpeed ")
                                                        .lambda()
                                                        .eq(
                                                                DeviceWeatherData::getDeviceId,
                                                                deviceId)
                                                        .apply(
                                                                " to_days(create_time) = to_days(now()) "));