ExecuteScalar Method

In This Topic

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

Syntax

Visual Basic
C#

'Declaration
 
Public Overrides Function ExecuteScalar() As Object

public override object ExecuteScalar()

Return Value

The first column of the first row in the result set.

Remarks

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 System.Data.Common.DbCommand.ExecuteReader method, and then performing the operations necessary to generate the single value from the data returned by a DbDataReaderBase.

Example

This example shows typical usage of ExecuteScalar method

csharp

using(PgSqlConnection conn = new PgSqlConnection(connectionString)) {
  conn.Open();
  PgSqlCommand cmd = conn.CreateCommand();
  cmd.CommandText = "SELECT count(*) as NumberOfRegions FROM regions";
  Int64 count = Convert.ToInt64(cmd.ExecuteScalar()); 
}

Visual Basic

Dim conn As New PgSqlConnection(connectionString)
conn.Open()
Dim cmd As PgSqlCommand = conn.CreateCommand()
cmd.CommandText = "SELECT count(*) as NumberOfRegions FROM regions"
Dim count As Int64 = Convert.ToInt64(cmd.ExecuteScalar()); 
conn.Close()

Requirements

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

Reference

DbCommandBase Class
DbCommandBase Members

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