function Get-SqlResults {
    [cmdletbinding()]
    Param (
        [System.Data.Odbc.OdbcCommand]$Query,
        [System.Data.Odbc.OdbcDataReader]$Reader
    )

    Begin {
        if ($Reader -eq $Null) {
            $Reader = $Query.ExecuteReader()
            $ReaderCreated = $True
        } else {
            $ReaderCreated = $False
        }
    }

    Process {
        while ($Reader.Read()) {
            $v = New-Object -TypeName 'System.Management.Automation.PSObject'
            foreach ($i in (0..($Reader.FieldCount - 1))) {
              Add-Member -InputObject $v -MemberType NoteProperty -Name $Reader.GetName($i) -Value $Reader.Item($i)
            }
            $v #return fetch results
        }
    }

    End {
        if ($ReaderCreated) {
            $Reader.Close()
        } else {
            $Dummy = $Reader.NextResult()
        }
    }
}

$Connection = New-Object system.data.odbc.odbcconnection
$Connection.ConnectionString = 'DSN=;Uid=;Pwd=' # тут, конечно, на самом деле правильная строка соединения
$Connection.Open()

$Query = New-Object system.data.odbc.odbccommand
$Query.Connection = $connection
$Query.CommandText = 'select dummy, level lv from dual connect by level <= 3'

if ($True) {
    $R = $Query.ExecuteReader()
    Get-SqlResults -Reader $R -Verbose
    $R.Close()
} else {
    Get-SqlResults -Query $Query -Verbose
}

$Connection.Close()