CODEWITHSUNDEEP
sqlsql-serverdivide
Justin
Justin

Reputation: 131

SQL Divide by Zero Error

I have an annoying problem which is stopping me from generating some data; The SQL job has 23 steps in total and fails on the 21st. 

-- Step 21 Create the table z1QReportOverview
-- Create z1QReportProjectOverview.sql
-- Project Overview - By Category (Part 4).sql
USE database
SELECT z1QReportProjectOverview1.[ERA Category] AS Category,
z1QReportProjectOverview1.[Total Projects Signed],
z1QReportProjectOverview1.[Total Spend Under Review],
z1QReportProjectOverview1.[Avg. Project Size],
z1QReportProjectOverview2.[Work in Progress],
z1QReportProjectOverview2.[Implemented],
z1QReportProjectOverview2.[No Savings],
z1QReportProjectOverview2.[Lost],
CONVERT(decimal(18,0),[Lost])/CONVERT(decimal(18,0),[Total Projects Signed]) AS [Loss Ratio],
z1QReportProjectOverview2.[Completed],
(
    CONVERT(decimal(18,0),([Completed]+[Implemented]))/
    CONVERT(decimal(18,0),([Completed]+[Implemented]+[Lost]))
) 
AS [Success Ratio],
z1QReportProjectOverview3.[Avg. Spend] AS [Average Spend],
z1QReportProjectOverview3.[Avg. Savings] AS [Average Savings],
z1QReportProjectOverview3.[Avg. Savings %] AS [Average Savings %]
INTO dbo.z1QReportProjectOverview
FROM dbo.z1QReportProjectOverview1
JOIN dbo.z1QReportProjectOverview2
ON (z1QReportProjectOverview1.[ERA Category] = z1QReportProjectOverview2.[ERA    Category])
JOIN dbo.z1QReportProjectOverview3
ON (z1QReportProjectOverview2.[ERA Category] = z1QReportProjectOverview3.[ERA     Category])
ORDER BY Category

I believe I know what is causing the divide by zero error.

The 'Lost' field is made up of three fields and in some cases (very rare) all 3 fields are 0 resulting in a 0 in the 'Lost' field.

I believe this is the main cause of the error but there is a second division there as well, I am pretty rubbish at SQL hence my question:

Where should I put the CASE WHEN clause?

-Most likely written this bit wrong as well :( "CASE When [Lost] = 0 SET [Total Projects Signed] = 0"

Any advice is much appreciated!

Upvotes: 2

Views: 814

Answers (4)

Justin
Justin

Reputation: 131

@Tanner:

So laying out the code like this should work just fine right?

CONVERT(decimal(18,0),[Lost])/CONVERT(decimal(18,0),[Total Projects Signed]) AS [Loss Ratio],
CASE 
 -- check if either value is 0 (which will cause error)
 WHEN CONVERT(decimal(18,0),[Lost]) = 0
   OR CONVERT(decimal(18,0),[Total Projects Signed]) = 0
 -- if so, return 0
 THEN 0
 -- otherwise perform calculation
ELSE CONVERT(decimal(18,0),[Lost])/CONVERT(decimal(18,0),[Total Projects Signed])
END AS [Loss Ratio]
z1QReportProjectOverview2.[Completed],
(
    CONVERT(decimal(18,0),([Completed]+[Implemented]))/
    CONVERT(decimal(18,0),([Completed]+[Implemented]+[Lost]))
) 
AS [Success Ratio],

Upvotes: 0

Mahesh
Mahesh

Reputation: 8892

You can use CASE as to check if the dividing value is 0 or not.

CASE WHEN CONVERT(decimal(18,0),[Lost]) <> 0 THEN 
        CONVERT(decimal(18,0),[Lost])/CONVERT(decimal(18,0),[Total Projects Signed]) 
     ELSE 0 END AS [Loss Ratio],
z1QReportProjectOverview2.[Completed],
CASE WHEN CONVERT(decimal(18,0),([Completed]+[Implemented]+[Lost])) <> 0 THEN 
      (CONVERT(decimal(18,0),([Completed]+[Implemented]))/CONVERT(decimal(18,0),([Completed]+[Implemented]+[Lost]))) 
    ELSE 0 END AS [Success Ratio],

Upvotes: 2

Tanner
Tanner

Reputation: 22743

You can use CASE WHEN like so:

CASE 
     -- check if either value is 0 (which will cause error)
     WHEN CONVERT(decimal(18,0),[Lost]) = 0
       OR CONVERT(decimal(18,0),[Total Projects Signed]) = 0
     -- if so, return 0
     THEN 0
     -- otherwise perform calculation
     ELSE CONVERT(decimal(18,0),[Lost])/CONVERT(decimal(18,0),[Total Projects Signed])
END AS [Loss Ratio]

Upvotes: 2

Pரதீப்
Pரதீப்

Reputation: 93724

Use NULLIF to handle divide by zero error

........
Isnull(CONVERT(DECIMAL(18, 0), [Lost]) / NULLIF(CONVERT(DECIMAL(18, 0), [Total Projects Signed]), 0), 0) AS [Loss Ratio],
Isnull(CONVERT(DECIMAL(18, 0), ( [Completed] + [Implemented] )) /
                        NULLIF(CONVERT(DECIMAL(18, 0), ( [Completed] + [Implemented] + [Lost] )), 0), 0) AS [Success Ratio], 
........

Upvotes: 3

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