GROUP_CONCAT很奇怪

Question

I use three tables with an inner join on 'user.ID'='email.ID' and 'user.ID'='telephone.ID'.

Every user has a name and an ID. Each email has a username, the email address itself and a corresponding userID. Each telephone number has a username, the number itself and a corresponding userID. It is possible for a user to have any amount of email addresses and telephone numbers.

I managed to output a users email addresses by selecting them like this:

GROUP_CONCAT(email.Address SEPARATOR ',') AS Address,
GROUP_CONCAT(email.Username SEPARATOR ',') AS eUsername

I then converted it into an array:

$Address = explode(",", $row["Address"]);
$eUsername = explode(",", $row["eUsername"]);

And printed it like this:

  for($i = 0;$i<count($Address);$i++) {
    echo $eUsername[$i] .': '. $Address[$i].'<br>';
  }

This is the printed table:

I then just did the same thing with the telephone numbers

Selecting:

GROUP_CONCAT(telephone.Number SEPARATOR ',') AS Number,
GROUP_CONCAT(telephone.Username SEPARATOR ',') AS tUsername

Converting:

$Number = explode(",", $row["Number"]);
$tUsername = explode(",", $row["tUsername"]);

Printing:

for($i = 0;$i<count($Number);$i++) {
    echo $tUsername[$i] .': '. $Number[$i].'<br>';
  }

But this messed up the whole table:

I don´t get why it prints the email addresses three times and just doesn´t print anything in the 'Telephone' coloumn although the second for loop is echoed into the most right coloumn.

Sorry for the long post and thanks for any help.

EDIT:

Here is my full SQL query:

SELECT user.Name AS Name, user.ID AS ID,
GROUP_CONCAT(email.Address SEPARATOR ',') AS Address,
GROUP_CONCAT(email.Username SEPARATOR ',') AS eUsername,
GROUP_CONCAT(telephone.Number SEPARATOR ',') AS Number,
GROUP_CONCAT(telephone.Username SEPARATOR ',') AS tUsername
FROM user
INNER JOIN email ON user.ID=email.ID
INNER JOIN telephone ON user.ID=telephone.ID
WHERE Name REGEXP '$searchterm'
GROUP BY ID

The WHERE statement is not final. This is just for testing.

Answer 1

The simplest solution is to use distinct:

SELECT u.Name AS Name, u.ID AS ID,
       GROUP_CONCAT(DISTINCT e.Address SEPARATOR ',') AS Address,
       GROUP_CONCAT(DISTINCT e.Username SEPARATOR ',') AS eUsername,
       GROUP_CONCAT(DISTINCT t.Number SEPARATOR ',') AS Number,
       GROUP_CONCAT(DISTINCT t.Username SEPARATOR ',') AS tUsername
FROM mitglied u INNER JOIN
     email e
     ON u.ID = e.ID INNER JOIN
     telephone t
     ON u.ID = t.ID
WHERE u.Name REGEXP '$searchterm'
GROUP BY u.ID, u.name;

Notes:

• I assume that mitglied is users.
• Table aliases make the query easier to write and to read.
• Qualified column names are recommended whenever you have multiple table references.