Symptoms
When you attempt to use the COMPUTE BY clause with the Microsoft SQL Server .NET Data Provider, you receive the following exception:

An unhandled exception of type ‘System.InvalidOperationException’ occurred in system.data.dll.
Additional information: COMPUTE BY statements not supported. Note The COMPUTE BY clause in a SQL Server statement generates subtotals within the result set.
Resolution
This behavior is caused by a limitation of the SQL Server .NET Data Provider.
The SQL Server .NET Data Provider does not support all SQL syntax statements.