sql join repeating results - php

Question

I need to make a list printing all the clients ordered by the gym name, but it's repeating the gym name the same number of gym's clients. If gym1 have 4 clients, the echo is printed 4 times.
The tables/columns are:
members (id, gym, name, etc...)
and
gym (gymID, gym_name, etc...).
member.gym is to know to what gym the client belongs (gym.gymID)
if ($stmt = $mysqli->prepare(" SELECT DISTINCT g.*, m.*
FROM gym g
INNER JOIN members m ON m.gym = g.gymID")) {
$stmt->execute();
$result = $stmt->get_result();
while ($row = $result->fetch_array()) {
echo 'Sport center: ' . $row['gym_name'] . '<br>';
// here print the gym's clients list
}
}
DISTINCT is not working... What is the problem??

Answer 1

That's the normal behavior.
Example.
Consider the following tables
Table "gym"
-----------
gym_id | gym_name
-------+----------
1 | Gym A
2 | Gym B
Table "members"
---------------
member_id | gym_id | member_name
----------+--------+------------
1 | 1 | Bob
2 | 1 | Jeff
And now, execute this query:
select g.gym_id, g.gim_name, m.member_id, m.member_name
from gym as g
inner join members as m on g.gym_id = m.gym_id;
Result:
gym_id | gym_name | member_id | member_name
-------+----------+-----------+-------------
1 | Gym A | 1 | Bob
1 | Gym B | 2 | Jeff
That happens because each row in the gym table is matched with a row in the members name. Even if you use select distinct, the result would be the same, because every row is different.
I think what you want is an output like this:
Gym A
Bob
Jeff
Although that can be done directly in SQL, it's easier to handle it directly with PHP, because doing it in SQL would be a real pain in the neck would require writing quite a complex query. I'm not quite good with PHP, but it could be something like this:
/*
You don't need "DISTINCT", but you need "ORDER BY" to make this work
*/
if ($stmt = $mysqli->prepare(" SELECT g.*, m.*
FROM gym g
INNER JOIN members m ON m.gym = g.gymID
ORDER BY g.gymID")) {
$stmt->execute();
$result = $stmt->get_result();
$gym = "";
while ($row = $result->fetch_array()) {
if($row['gym_name'] != $gym)
echo 'Sport center: ' . $row['gym_name'] . '<br>';
echo ' Member: ' . $row['member_name'] . '<br>';
$gym = $row['gym_name'];
}
}

Answer 2

First, drop the DISTINCT and slap in an ORDER BY:
SELECT g.*, m.*
FROM gym g
INNER JOIN members m ON m.gym = g.gymID
ORDER BY g.name;
Now, adjust your PHP code to only print the gym name if it's different from the last gym you printed.

Answer 3

SELECT g.*, m.*
FROM gym g
INNER JOIN members m ON m.gym = g.gymID
ORDER BY g.name,gym_clients;
I dont know the name of Gym Name column & gym Client Column So, Please Change the name if they are not correctly spelled.
I hope this will work for you

Answer 4

This should work:
SELECT *
FROM gym g
LEFT JOIN members m
ON g.gym_ID=m.gym_id
GROUP BY g.gym_name