${if(len(start_time) == 0,"","and SUBSTR(T1.H_CPERIOD,1,7) = '" +start_time+ "'")}我把SUBSTR(T1.H_CPERIOD,1,7)用add_mmonth 处理一下不行,因为再${}里面,得用帆软得函数,然后我改成这样也不行${if(len(start_time) == 0,"","and SUBSTR(T1.H_CPERIOD,1,7) = '" +MONTHDELTA(start_time ,-1)+ "'")}也不行注:SUBSTR(T1.H_CPERIOD,1,7)和start_time均为字符串