I have set a default query
$query = "SELECT Image, ISBN, Name, Vol, Release_date, publisher, price FROM products p order by Name,vol";
echo "<a href = ???>Date</a>";
so that the query can be changed in sorting by date after clicking? Thank you!
The sorting/ordering parameter is order by Name,vol
at the end of the query.
So you might make it as a variable depending on whether the GET['date']
is present from href.
<?php
$sortvar = isset($_GET['date']) ? 'order by '. $_GET['date'] : 'order by Name,vol';
if (isset($_GET['ndsn']) && isset($_GET['date']) )
$sortvar = 'order by '. $_GET['date'] . ',' . $_GET['ndsn'];
$query = "SELECT Image, ISBN, Name, Vol, Release_date, publisher, price FROM products p " . $sortvar;
echo "<a href = '?date=Date'>Date</a><br>";
echo "<a href = '?date=Date&ndsn=NDSN'>Date & NDSN</a><br>";
echo $query;
you MUST escape GET parameters or parametrize your result query when adding GET parameters into it, cause of SQL-injections possibility.