SQL時間戳提取時間和組由

Question

Select to_char(Contactdate,'HH24:MI:SS') 
from CHSTAGING 

我有這個SQL查詢，我想從時間戳提取時間。但是，一旦我使用GROUP BY它不起作用。

GROUP BY to_char(Contactdate,'HH24:MI:SS') 

下面是如何在數據集中顯示時間戳的示例。我想在同一時間將各行組合在一起。即。 HH：MI：SS

Answer 1

放入一個CTE，如果它打起來......

with CTE as 
(
    select mt.*, to_char(contactdate, 'HH24:MI:SS') as ContactTime 
    from mytable mt 
) 
select ContactTime, count(somefield) as countedfield 
from CTE 
group by ContactTime 

Answer 2

試試這個： -

Select cast(contactdate as time) as Tim 
from 
INTERACT.UACI_CHSTAGING_MSISDN 
group by cast(contactdate as time) 

OR 

Select tim from 
(
Select to_char(Contactdate,'HH24:MI:SS') as tim 
from INTERACT.UACI_CHSTAGING_MSISDN 
) a 
group by tim 

希望這有助於:-)