Session.ExecuteScalar(String) Method

Executes the specified SQL query and returns the first column of the first row in the result set returned by the query.

Namespace: DevExpress.Xpo

Assembly: DevExpress.Xpo.v24.2.dll

Declaration

C#

public object ExecuteScalar(
    string sql
)

VB.NET

Public Function ExecuteScalar(
    sql As String
) As Object

Parameters

Name	Type	Description
sql	String	Specifies an SQL statement.

Returns

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

Remarks

Use the ExecuteScalar method to query data stores for a single or aggregate value, without having to retrieve a result set.

The following example demonstrates how to use this method. Here, session is the Session instance.

C#

public int GetOrdersCount() {
    return (int)session.ExecuteScalar(
        "SELECT COUNT(*) FROM [Northwind].[dbo].[Orders]"
    );        
}

VB.NET

Public Function GetOrdersCount() As Integer
    Return CInt(session.ExecuteScalar( _
        "SELECT COUNT(*) FROM [Northwind].[dbo].[Orders]"))
End Function

To learn more about executing SQL queries in XPO, refer to Direct SQL Queries.

Note

The ExecuteScalar method sends queries directly, so the correct query syntax depends on a particular database server.