这个数据集里的空冷前降温数据查不到,是哪里不对吗select a.*,b.空冷后温降 from(select a.stat_date,a.炉盖温度平均值 - b.空冷前温度平均值 as 空冷前温降 from(select stat_date,CONVERT(average_value,DECIMAL(12,2)) as 炉盖温度平均值 from mom_process_index_daily_statistic where pt_number in("KD_JH15#16#_15#_KLQWD") AND DATE_FORMAT(stat_date,'%Y-%m-%d') >= '${DATEINMONTH(TODAY(),1)}' AND DATE_FORMAT(stat_date,'%Y-%m-%d') <='${today()}')aleft join(select stat_date,CONVERT(average_value,DECIMAL(12,2)) as 空冷前温度平均值 from mom_process_index_daily_statistic where pt_number in("KD_JH15#16#_15#_KLQWD") AND DATE_FORMAT(stat_date,'%Y-%m-%d') >= '${DATEINMONTH(TODAY(),1)}' AND DATE_FORMAT(stat_date,'%Y-%m-%d') <= '${today()}')bon a.stat_date = b.stat_date)aleft join(select a.stat_date,b.空冷前温度平均值 - a.空冷后温度平均值 as 空冷后温降 from(select stat_date,CONVERT(average_value,DECIMAL(12,2)) as 空冷后温度平均值 from mom_process_index_daily_statistic where pt_number in("KD_JH15#16#_15#_KLHWD") AND DATE_FORMAT(stat_date,'%Y-%m-%d') >= '${DATEINMONTH(TODAY(),1)}' AND DATE_FORMAT(stat_date,'%Y-%m-%d') <= '${today()}')aleft join(select stat_date,CONVERT(average_value,DECIMAL(12,2)) as 空冷前温度平均值 from mom_process_index_daily_statistic where pt_number in("KD_JH15#16#_15#_KLQWD") AND DATE_FORMAT(stat_date,'%Y-%m-%d') >= '${DATEINMONTH(TODAY(),1)}' AND DATE_FORMAT(stat_date,'%Y-%m-%d') <= '${today()}')bon a.stat_date = b.stat_date)bon a.stat_date = b.stat_dateorder by a.stat_date asc