Echo rows via JOIN in MySQL/PHP (?) - php

Question

I wanna be able to echo out if Groupname and Username are connected correctly, where the current userid (saved in a session) is $uid.
I've been sitting for hours trying all kinds of JOINs and the closest I've gotten is having it output 1/? members for each team, but not all of them.
EDIT:
$uid = $_SESSION['uid'];
$sql = "SELECT * FROM group
INNER JOIN usergroup ON group.groupid=usergroup.groupid
WHERE usergroup.userid=$uid";
$result=$mysqli->query($sql);
if(mysqli_num_rows($result)>0) {
while($row = mysqli_fetch_array($result)) {
$gid = $row['groupid'];
$sql2 = "SELECT * FROM user
INNER JOIN usergroup ON user.userid=usergroup.userid
WHERE usergroup.groupid=$gid";
$result2=$mysqli->query($sql2);
$row2 = mysqli_fetch_array($result2);
echo "<td>".$row['groupname']."</td>";
echo "<td>".$row2['username']."</td>";
echo "<td>".$row['groupid']."</td>";
}
}
Thing is, that it kinda works well, except that it doesn't print all the groupmembers names out, it prints out just one. Which one seems to depend on the order in the table.

Answer 1

You did not have a loop on the second query's resultset. However, it is not needed to have a second SQL query. Just do it in one go; SQL was designed for that.
Also, you'll have much simpler code:
$uid = $_SESSION['uid'];
// Select everything you need in one go (join user table as well)
$sql = "SELECT group.group_id, group.groupname, user.username
FROM group
INNER JOIN usergroup ON group.groupid=usergroup.groupid
INNER JOIN user ON user.userid=usergroup.userid
WHERE usergroup.userid=$uid";
$result=$mysqli->query($sql);
// Don't need to call mysqli_num_rows if you continue like this:
while($row = mysqli_fetch_array($result)) {
echo "<td>".$row['groupname']."</td>";
echo "<td>".$row['username']."</td>";
echo "<td>".$row['groupid']."</td>";
}
Maybe you want to echo some <tr> and </tr> tags, or you"ll have everything in one row, like:
echo "<tr><td>".$row['groupname']."</td>"
."<td>".$row['username']."</td>"
."<td>".$row['groupid']."</td></tr>";

Answer 2

There you go: (you were missing nested while loop)
if(mysqli_num_rows($result)>0) {
while($row = mysqli_fetch_array($result)) {
$gid = $row['groupid'];
$sql2 = "SELECT * FROM user INNER JOIN usergroup ON user.userid=usergroup.userid WHERE usergroup.groupid=$gid";
$result2=$mysqli->query($sql2);
if(mysqli_num_rows($result2)>0) {
while($row2 = mysqli_fetch_array($result2)) {
echo "<td>".$row['groupname']."</td>";
echo "<td>".$row2['username']."</td>";
echo "<td>".$row['groupid']."</td>";
}
}
}
}
Side note: You could achieve the same results with just one SQL query, something like:
SELECT
*
FROM
usergroup ug
INNER JOIN
user u ON ug.userid = u.userid
GROUP BY
ug.id
and then in PHP (pseudo code just, do not copy-n-paste)
while($row => mysqli_fetch_array($result)) {
if (!isset($groupsWithUsers[$row['groupid']['users'])) {
$groupsWithUsers[$row['groupid']['users'] = array()
}
$groupsWithUsers[$row['groupid']['users'][$row['userid']] = $row;
}