getting max value error in syntax

[JLW]

I am trying to get the maximum item number that matches a specific invoice number

$get_item_number = mysql_query("SELECT MAX (ItemNumber) identifyorder WHERE InvoiceNumber = '$Invoice'");

this is the error I get:
"You have an error in your SQL syntax near '('ItemNumber') identifyorder WHERE InvoiceNumber = '402'' at line 1"

Can anyone tell me what is wrong with my syntax?

Sorry about that, I think I have been on the computer too long. I just realized what was wrong.

$get_item_number = mysql_query("SELECT MAX (ItemNumber) FROM identifyorder WHERE InvoiceNumber = '$Invoice'");

that works fine!!

[mrhappiness]

if i were a mysql server i would'nt know FROM which table i should read that value