Use the ExecuteScalar method to retrieve a single value, for example, an aggregate value, from a data source. This requires less code than using the ExecuteReader method, and then performing the operations that are required to generate the single value using the data returned by an OleDbDataReader.
A typical ExecuteScalar query can be formatted as in the following C# example:
The following example creates an OleDbCommand and then executes it using ExecuteScalar. The example is passed a string that is an SQL statement that returns an aggregate result, and a string to use to connect to the data source.