Seaquel
SQL Server error code

SQL Server error 8678

SQL Server raises error 8678 at severity 16, which marks a problem with the query or data that you can correct.

Cannot create the clustered index "%.*ls" on view "%.*ls" because the view references a SUM aggregate of a nullable expression. Consider adding a new COUNT_BIG aggregate over such nullable expression.
Msg8678
Severity16
Group8000–8999

Source: Database Engine events and errors