In IF statement with dates see whether a NULL exists - sql

Question

I have this query and i see if the AUD_CloseDate is > than todays date. Now i imagine these would be a NULL somewhere in AUD_CloseDate so in this statement i also want to check if there is a NULL value in AUD_CloseDate and if there is assign value 1900\01\01
SELECT ([Target Status] + '' + CAST(COUNT(*) AS NVARCHAR(255)) + ' of ' + CAST(#Total AS NVARCHAR(255))) AS TargetStatus, CAST(COUNT(*) AS FLOAT)/CAST(#Total AS FLOAT) AS [Count]
FROM (
SELECT CASE WHEN CONVERT(DATETIME,CONVERT(CHAR(10),DATEADD(DAY,0,t2.AUD_CloseDate), 101)) < CONVERT(DATETIME,CONVERT(CHAR(10),DATEADD(DAY,0,GETDATE()), 101))AND t1.[Status] in ('Open','Closed')
THEN 'Over Due: '
ELSE 'On Time: ' END AS [Target Status]
FROM #tmp1 t1 INNER JOIN dbo.Audit t2
ON t1.AUD_ID = t2.AUD_ID
WHERE t2.AUD_Deleted = 0
AND t2.AUD_LeadAuditor IN (SELECT ID FROM [dbo].[fx_SplitCommaSeperatedValues] (#LeadAssessor))
AND t2.AUD_Year = #Year
AND AUD_Quarter IN (SELECT ID FROM [dbo].[fx_SplitCommaSeperatedValues] (#Quarter)))DER

Answer 1

COALESCE is ANSI-compliant. Same syntax as ISNULL: COALESCE(t2.AUD_CloseDate,'19000101')

Answer 2

Why about a ISNULL() statement ?
ISNULL(t2.AUD_CloseDate,'19000101')
In you example :
SELECT ([Target Status] + '' + CAST(COUNT(*) AS NVARCHAR(255)) + ' of ' + CAST(#Total AS NVARCHAR(255))) AS TargetStatus, CAST(COUNT(*) AS FLOAT)/CAST(#Total AS FLOAT) AS [Count]
FROM (
SELECT CASE WHEN CONVERT(DATETIME,CONVERT(CHAR(10),DATEADD(DAY,0,ISNULL(t2.AUD_CloseDate,'19000101')), 101)) < CONVERT(DATETIME,CONVERT(CHAR(10),DATEADD(DAY,0,GETDATE()), 101))AND t1.[Status] in ('Open','Closed')
THEN 'Over Due: '
ELSE 'On Time: ' END AS [Target Status]
FROM #tmp1 t1 INNER JOIN dbo.Audit t2
ON t1.AUD_ID = t2.AUD_ID
WHERE t2.AUD_Deleted = 0
AND t2.AUD_LeadAuditor IN (SELECT ID FROM [dbo].[fx_SplitCommaSeperatedValues] (#LeadAssessor))
AND t2.AUD_Year = #Year
AND AUD_Quarter IN (SELECT ID FROM [dbo].[fx_SplitCommaSeperatedValues] (#Quarter)))DER

Answer 3

Use ISNULL function
ISNULL(AUD_CloseDate, '1900-01-01')
You are also:
adding 0 days to date
casting it to char(10)
, then casting again to date... Why?
You can achieve the same result withou these conversions, like this example:
SELECT
CASE
WHEN ISNULL(#a, '2014-01-29 13:50') < GETDATE()
THEN 'Over Due: '
ELSE 'On Time: '
END
Results 'Over due:'
SELECT
CASE
WHEN ISNULL(#a, '2014-01-29 15:00') < GETDATE()
THEN 'Over Due: '
ELSE 'On Time: '
END
Results 'On Time:'
** Now is 13:55 :)