Attempting to set a non-NULL- able column's value to NULL - sql

Question

I am getting attempting to set a non-NULL- able column's value to NULL
error when I use FOR XML PATH('')
Code:
select
fdp.POLICYNUMBER,
fdp.INSUREDNAME,
fdp.OWNERNAME,
fdp.AGENCYCODE,
p.WFWORKSTEPNAME,
fdpc.NIGO,
fdpc.NIGOREASON,
d.NIGOREQUIREMENT,
wci.WCSTATUS,
wci.DATECOMPLETED,
fdCI.NEWUNDERWRITINGUSER,
fdr.NBAMOUNT
into
#t
from
PINewBusiness p
join
FDPolicyDetails fdp on SUBSTRING(p.CFREPKEY, 9, LEN(p.CFREPKEY)) = fdp.PARENT_CASEID
and (p.WFWORKSTEPNAME = 'PendingRequirements' or
p.WFWORKSTEPNAME = 'FollowUpRequirements' )
join
FDProcessing fdpc on SUBSTRING(p.CFREPKEY, 9, LEN(p.CFREPKEY)) = fdpc.PARENT_CASEID
join
FDRounting fdr on SUBSTRING(p.CFREPKEY, 9, LEN(p.CFREPKEY)) = fdr.PARENT_CASEID
cross apply
(select NIGOREQUIREMENT + ', '
from FDNIGORequirements nr
where nr.PARENT_CASEID = fdpc.PARENT_CASEID
for xml path('')) D (NIGOREQUIREMENT)
--join FDNIGORequirements nr on SUBSTRING(p.CFREPKEY, 9, LEN(p.CFREPKEY)) = nr.PARENT_CASEID
cross apply
(select NIGOREQUIREMENT + ', '
from FDNIGORequirements nr
where nr.PARENT_CASEID = SUBSTRING(p.CFREPKEY,9,LEN(p.CFREPKEY))
for xml path('')) D (NIGOREQUIREMENT)
join
(select max(CREATEDDATETIME) as CREATEDDATETIME, PARENT_CASEID
from FDWelcomeCall
group by PARENT_CASEID ) wc on fdr.PARENT_CASEID = wc.PARENT_CASEID
join
FDWelcomeCall wci on wci.PARENT_CASEID = wc.PARENT_CASEID
and wci.CREATEDDATETIME = wc.CREATEDDATETIME
join
FDCaseInformation fdCI on SUBSTRING(p.CFREPKEY, 9, LEN(p.CFREPKEY)) = fdCI.PARENT_CASEID
where
p.WFSTEPENTRYTIME >= #sdate
and p.WFSTEPENTRYTIME <= #edate
order by
p.WFFLOWENTRYTIME desc

Answer 1

If you want to keep the rows with NULL values you must replace the nulls in the column that gives you the error, to do so you can use:
SELECT COALESCE([MyColumn],__ReplacementValue__) AS [MyColumn] FROM MyTable
or
SELECT ISNULL([MyColumn],__ReplacementValue__) AS [MyColumn] FROM MyTable
You can use one of them in the inner or outer SELECT.
Otherwise, if the row should not exist if that value is null you must filter it out by adding a WHERE clause:
WHERE [MyColumn] IS NOT NULL