En lösning skulle vara att göra ett underval av hela påståendet och tillämpa where-satsen på resultatet
select *
from (
select cast(de.ApprovalOrder AS VARCHAR(32))
+ cast(de.EntityCode AS VARCHAR(32))
+ isnull(cast(de.DelegationCode AS VARCHAR(32)), '') as 'RowID'
, *
from workflow.delegation_engine de
) de
where de.RowID IS NOT NULL
En annan lösning kan vara att upprepa hela satsen i WHERE-satsen
select cast(de.ApprovalOrder AS VARCHAR(32))
+ cast(de.EntityCode AS VARCHAR(32))
+ isnull(cast(de.DelegationCode AS VARCHAR(32)), '') as 'RowID' ,
*
from workflow.delegation_engine de
where cast(de.ApprovalOrder AS VARCHAR(32))
+ cast(de.EntityCode AS VARCHAR(32))
+ isnull(cast(de.DelegationCode AS VARCHAR(32)), '') IS NOT NULL
Eller så kan du testa varje enskilt fält för NULL
select cast(de.ApprovalOrder AS VARCHAR(32))
+ cast(de.EntityCode AS VARCHAR(32))
+ isnull(cast(de.DelegationCode AS VARCHAR(32)), '') as 'RowID' ,
*
from workflow.delegation_engine de
where de.ApprovalOrder IS NOT NULL
AND de.EntityCode IS NOT NULL