testing for match in mySQL

[wxdqz]

I want to make sure the data I am inserting into a table is not duplicate data. I need to know the syntax for row **. The error I am getting is "Warning: Supplied argument is not a valid MySQL result resource in ../pricingTEST.php" Here is my code:

$instest1 = mysql_query("Select * from Orders where CustomerID = '$CustomerID' and NickName = '$NickName' and Date='$InsertDate1' and Time='$InsertTime1' ");
if (!$instest1)
{
echo("<P>Error performing query: " .
mysql_error() . "</P>");
exit();
}
**while (! $row = mysql_fetch_array $insttest1))
{
//perform insert
$sql1 = "INSERT INTO Orders SET " .
$sql1 = "CustomerID='$CustomerID', " .
$sql1 = "NickName='$NickName', " .
$sql1 = "Date='$InsertDate1', " .
$sql1 = "Time='$InsertTime1', " .
$sql1 = "Hide='1' ";

Thank you!!!