在mysql php中选择相同的字段[关闭]

I created a table that contains sender | message | sent_to and PHP page that shows the messages

mysql_connect("localhost", "root", "");
mysql_select_db("mydb");

$result = mysql_query("SELECT * FROM `msg`");
$num_rows = mysql_num_rows($result);
while($info = mysql_fetch_array($result)){
$msg = $info['message'];
echo "</br> $msg";
}

it shows all messages in the table that's ok, but I want to show the message where the sender is the same sender. I hope to find a way to do that! Thank You :)

This is a shot in the dark.

mysql_connect("localhost", "root", "");
mysql_select_db("mydb");

$result = mysql_query("SELECT * FROM `msg` ORDER BY sender");
$sender = null;

while($info = mysql_fetch_array($result)){
    $msgSender = $info['sender'];

    if (isnull($sender) || $sender !== $msgSender)
    {
        echo "Messages for " . $msgSender;
        $sender = $msgSender;
    }

    echo "</br> $info['message']";
}

First just choose the same sender

$id = 1;
$result = mysql_query("SELECT * FROM `msg` WHERE `sender` = '{$id}'");

Then if sender, message and sent_to are all fields in the database then just do this

while($info = mysql_fetch_array($result)){
    echo $info['sender'] . " " . $info['message'] . " " . $info['sent_to'] . "<br />";
}

$sender_id = 123;
$result = mysql_query("SELECT * FROM `msg` WHERE `sender` = '{$sender_id}'");