How do I handle Error in sql queries?

开发者_如何转开发For sql queries like..

select Quantity_Books/datepart(hour,Rent_Hour) from Rent_Book where (some conditions..)

They will return error when datepart(hour,Rent_Hour) is 0.

If sth like that Happens, I would like to show 0.

I know I should use case when But I am not really sure how..

Or any other better method?

You'd simply test the value first

select
    CASE
       WHEN datepart(hour,Rent_Hour) = 0 THEN 0
       ELSE Quantity_Books/datepart(hour,Rent_Hour)
    END
from
    Rent_Book where (some conditions..)

Alternatively, use NULL rules

ISNULL((Quantity_Books / (NULLIF(datepart(hour,Rent_Hour), 0))), 0)

select case when datepart(hour,Rent_Hour)<>0 then Quantity_Books/datepart(hour,Rent_Hour) else 0 end as col ...