case when then 中判斷null的方法

 

--下列SQL無效
SELECT CASE MAX(T.CREATE_TIME) WHEN NULL THEN TO_DATE('2019-03-05 00:00:01','yyyy-MM-dd hh24:mi:ss') ELSE  MAX(T.CREATE_TIME) END AS CREATE_TIME FROM  rpt_daily_transaction T;


--須要用下面SQL
SELECT CASE  WHEN MAX(T.CREATE_TIME)  IS  NULL THEN TO_DATE('2019-03-05 00:00:01','yyyy-MM-dd hh24:mi:ss') ELSE  MAX(T.CREATE_TIME) END AS CREATE_TIME FROM  rpt_daily_transaction T;