Render table and render_sql

Hi I don’t understand what’s worng with my code.
I visualize my sql correctly but when I try to update using render_table it doesn’t work.
I see bold fields in grid but the row in database don’t change.


error_reporting(E_ALL ^ E_NOTICE);

// Variabili
$grid_column = "sic,descrizione_bene,reparto_stanza,unita_operativa,codice_interno";

$grid_merged_column = "sic,descrizione,reparto_stanza,unita_operativa,codice_interno";
$sql_merged_column 	= "select sic, concat(descrizione_bene, ' - ', costruttore) as descrizione, 
					reparto_stanza, unita_operativa, costruttore, codice_interno 
					from apparecchiatura"; 

//adds the connector engine
mysql_query("SET CHARACTER SET 'utf8'");
//initializes the connector object
$conn = new GridConnector($res);             

//loads data the method takes: the table's name, the id field, a list of fields to load

if ($conn->is_select_mode())  
	// code for loading data
	// code for other operations - i.e. update/insert/delete	(si può modificare solo una tabella)

Ok, I solved.

I add the id to $sql_merged_column that contain the sql instruction for retrieve the information.
Without this id, the update doesn’t work !! :smiley: