Question

I have a mysql table which has data from all flight bookings on my booking system. When a user books a flight, the details of that booking are stored in that table along with their username.

Now, I’m making a page where all of the user’s previous flights are shown in a HTML table, and everything works except the code which filters results to those only from that user.

This is the (part of) code I’m using;

$query_string = "SELECT name, seats, departure, destination, class, username, miles, timestamp FROM $tablename WHERE username IN ('$username')";

The username field is where the user who booked the flight’s username is stored, and the $username variable contains the current logged in user’s username. What I’m trying to do is only show the fields where $username matches username (hence only showing bookings for the current user).

When I use the above code without WHERE username IN ('$username'), it displays all the data, but when I add the above code, it displays nothing when there are matches.

If anyone could help fix my code I would greatly appreciate it.
Thanks!

Answer 1

You’re using IN incorrectly. IN compares comma-separated lists of strings or values. This can be literal:

WHERE username IN ('user1', 'user2', 'user3')

OR it can come from a subquery:

WHERE username IN (SELECT username FROM users)

If you want an exact match, your WHERE clause should be

WHERE username = '$username'

If that still doesn’t work, you MUST verify that you’re sending your database the correct query.

echo $query_string;