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IDbCommand.ExecuteScalar Method

Executes the query, and returns the first column of the first row in the resultset returned by the query. Extra columns or rows are ignored.

Namespace:  System.Data
Assembly:  System.Data (in System.Data.dll)

Object ExecuteScalar()

Return Value

Type: System.Object
The first column of the first row in the resultset.

Use the ExecuteScalar method to retrieve a single value (for example, an aggregate value) from a database. This requires less code than using the ExecuteReader method, and then performing the operations necessary to generate the single value using the data returned by an IDataReader.

A typical ExecuteScalar query can be formatted as in the following C# example:

 CommandText = "select count(*) as NumberOfRegions from region";
 Int32 count = (int) ExecuteScalar();

If the first column of the first row in the result set is not found, a null reference (Nothing in Visual Basic) is returned. If the value in the database is null, the query returns DBNull.Value.

The following example creates an instance of the derived class, SqlCommand, and then executes it using ExecuteScalar. The example is passed a string that is a Transact-SQL statement that returns an aggregate result, and a string to use to connect to the data source.


public void CreateSqlCommand(
    string queryString, SqlConnection connection) 
{
    SqlCommand command = new 
        SqlCommand(queryString, connection);
    command.Connection.Open();
    command.ExecuteScalar();
    connection.Close();
}


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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