Get transaction log backup LSN (log sequence number) for a database

Get-DatabaseLastLogBackupLSN.ps1

[Void][System.Reflection.Assembly]::LoadWithPartialName('Microsoft.SqlServer.SMO');
[Void][System.Reflection.Assembly]::LoadWithPartialName('Microsoft.SqlServer.SMOExtended');

$SQLInstance = New-Object "Microsoft.SqlServer.Management.Smo.Server" "localhost";
$DatabaseName = "TestDB";
$QueryStmt =
@"
	SELECT	last_log_backup_lsn
	FROM	sys.database_recovery_status
	WHERE	database_id = DB_ID('$DatabaseName');
"@;

$QueryResult = $SQLInstance.ConnectionContext.ExecuteWithResults($QueryStmt);

if ($QueryResult.Tables[0].Rows[0] -eq $null)
{ Write-Output "Empty result set, database doesn't exist."; }
else
{
	$LastLogBackupLSN = $QueryResult.Tables[0].Rows[0]["last_log_backup_lsn"];
	if ($LastLogBackupLSN -is [System.DBNull])
		{ Write-Output "Last Log Backup LSN is NULL, full backup not run yet or database in in simple recovery model."; }
	else
		{ Write-Output "Last Log Backup LSN for database [$($DatabaseName)] is $($LastLogBackupLSN)."; };
};

Get-SQLInstance.ps1

[Void][System.Reflection.Assembly]::LoadWithPartialName('Microsoft.SqlServer.SMO');
[Void][System.Reflection.Assembly]::LoadWithPartialName('Microsoft.SqlServer.SMOExtended');

$SQLInstance = New-Object "Microsoft.SqlServer.Management.Smo.Server" "localhost;
$QueryStmt =
@"
	SELECT	last_log_backup_lsn
	FROM	sys.database_recovery_status
	WHERE	database_id = DB_ID('$DatabaseName');
"@;

$QueryResult = $SQLInstance.Databases["master"].ExecuteWithResults($QueryStmt);