1.按小时统计数量
SELECT TO_CHAR(RECEIVE_TIME,‘HH24‘) HOUR ,COUNT(*) N FROM PH_PRESCRIPTION P WHERE TO_CHAR(P.RECEIVE_TIME ,‘YYYY-MM-DD‘)=‘2018-12-05‘ GROUP BY TO_CHAR(RECEIVE_TIME,‘HH24‘) ORDER BY TO_CHAR(RECEIVE_TIME,‘HH24‘);
原文：https://www.cnblogs.com/vipsoft/p/10695303.html