How to Avoid Divide by Zero in a Calculated Column

I am trying to protect a divide by zero in my last column.

SELECT
max(dbo.getmonthdate(t.TransDate)),
max(dbo.getmonth(t.TransDate)),
Sum(CASE t.TransType WHEN 1 THEN 1 ELSE 0 END) AS PassportsIssued,
Sum(CASE t.TransType WHEN 7 THEN 1 ELSE 0 END) AS PassportVerifications,
Sum(CASE t.TransType WHEN 8 THEN 1 ELSE 0 END) AS SkillVerifications,(Sum(CASE t.TransType WHEN 7 THEN 1 ELSE 0 END) + Sum(CASE t.TransType WHEN 8 THEN 1 ELSE 0 END))/Sum(CASE t.TransType WHEN 1 THEN 1 ELSE 0 END) AS Calculated

The problem is that
(CASE t.TransType WHEN 1 THEN 1 ELSE 0 END)
may sometimes be zero in which case I need to return "No Ratio Available"

Can Anyone help? I understand I may have to use a nested case statement or something!
LVL 1
MayoorPatelAsked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

TimCotteeHead of Software ServicesCommented:
Select MaxMonthDate,MaxMonth,PassportsIssued,PassportVerifications,SkillVerifications, Case When PassportsIssued = 0 Then 'No Ratio Available' Else Cast((PassportVerifications + SkillVerifications) / PassportsIssued As Varchar(20)) End As Calculated From
(
SELECT
max(dbo.getmonthdate(t.TransDate)) As MaxMonthDate,
max(dbo.getmonth(t.TransDate)) As MaxMonth,
Sum(CASE t.TransType WHEN 1 THEN 1 ELSE 0 END) AS PassportsIssued,
Sum(CASE t.TransType WHEN 7 THEN 1 ELSE 0 END) AS PassportVerifications,
Sum(CASE t.TransType WHEN 8 THEN 1 ELSE 0 END) AS SkillVerifications,(Sum(CASE t.TransType WHEN 7 THEN 1 ELSE 0 END) + Sum(CASE t.TransType WHEN 8 THEN 1 ELSE 0 END))/Sum(CASE t.TransType WHEN 1 THEN 1 ELSE 0 END) AS Calculated
From MyTable) Calculation

For example, doing a secondary select means that you can work with the totals without having to recalculate them.
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
LowfatspreadCommented:
like this...

Select MaxMonthDate,MaxMonth,PassportsIssued,PassportVerifications,SkillVerifications
     , Case When PassportsIssued = 0 Then 'No Ratio Available'
            Else Convert(varchar(30),passportVerifications + (skillverifications * 1.00/passportsissued))
            End As Calculated
  From
(
SELECT
max(dbo.getmonthdate(t.TransDate)) As MaxMonthDate,
max(dbo.getmonth(t.TransDate)) As MaxMonth,
Sum(CASE t.TransType WHEN 1 THEN 1 ELSE 0 END) AS PassportsIssued,
Sum(CASE t.TransType WHEN 7 THEN 1 ELSE 0 END) AS PassportVerifications,
Sum(CASE t.TransType WHEN 8 THEN 1 ELSE 0 END) AS SkillVerifications
From MyTable) as X
0
Ved Prakash AgrawalDatabase Consultant/Performance ArchitectCommented:
SELECT
max(dbo.getmonthdate(t.TransDate)),
max(dbo.getmonth(t.TransDate)),
Sum(CASE t.TransType WHEN 1 THEN 1 ELSE 0 END) AS PassportsIssued,
Sum(CASE t.TransType WHEN 7 THEN 1 ELSE 0 END) AS PassportVerifications,
Sum(CASE t.TransType WHEN 8 THEN 1 ELSE 0 END) AS SkillVerifications,
CASE WHEN t.TransType =1 THEN  CAST((Sum(CASE t.TransType WHEN 7 THEN 1 ELSE 0 END) + Sum(CASE t.TransType WHEN 8 THEN 1 ELSE 0 END))/Sum(CASE t.TransType WHEN 1 THEN 1 ELSE 0 END)  as varchar(2000) ) ELSE 'No Ratio Available' END AS Calculated
0
MayoorPatelAuthor Commented:
Hi there I forgot to add that there was this in the from clause

FROM GetCardtypes(3) ct inner join
tblTransactions t
on ct.cardtypeID=t.cardTypeID
inner join tblUsers u on
      u.PHID = t.IssuedToID

Can anyone help add this to the solutions you have provided.
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Microsoft SQL Server

From novice to tech pro — start learning today.