Msg 8117, Level 16, State 1, Line 1
Operand data type %1! is invalid for %2! operator.
This error message appears when the datatype is not allowed for the chosen operator.
The T-SQL statement can be parsed, but causes the error at runtime.
Error of the Severity level 16 are generated by the user and can be fixed by the SQL Server user.
All versions of SQL Server.
SELECT CustomerID, SUM(OrderDate)
GROUP BY CustomerID
In the above example the error is raised, because the column OrderDate is of DATETIME datatype. As it makes logically very little sense to sum up values of that datatype in the SUM() aggregate function, the use of this operand is invalid for the SUM operator.