Anj Jo Anj Jo - 2 years ago 64
PHP Question

PHP: While loop does not run when the condition is true

The following PHP program is to search for a student number in database and display the details if found or give a message if it does not exist.



$connection = mysql_connect("localhost", "root", "")
or die("couldn't connect to the server");

$db = mysql_select_db("student", $connection)
or die("<b>connection fails");

$query = "select * from performance where Number = '$sno'";

if($result = mysql_query($query))
echo "<table border = 1 align = center>";
echo "<tr>";
echo "<th>Number<th>Name<th>Address<th>Mobile Number";
echo "</tr>";

while($row = mysql_fetch_array($result))
echo "<tr>";
echo "<th>",$row['Number'],"</th>";
echo "<th>",$row['Name'],"</th>";
echo "<th>",$row['Address'],"</th>";
echo "<th>",$row['MobileNo'],"</th>";
echo "</tr>";
echo "</table>";
echo "The student data updated";

echo "<b>Customer number does not exist";


If i search for a number which does not exist the else block runs. When i give a number which exists then the if block runs but the while loop does not run. Can anybody help me out? Database field names are correct.

Answer Source

mysql_query() only returns false if there's an error in the query. Not finding any matching rows is not an error. To tell if any rows were found use mysql_num_rows().

$result = mysql_query($query) or die("Query error: " . mysql_error());
if (mysql_num_rows($result) > 0) {
} else {
    echo "<b>Customer number does not exist</b>";
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