How can I perform these MySQL subqueries in a cleaner way? - php

Question

Using legacy code which uses mysql instead of mysqli/pdo so don't worry about this, I'll update the queries for this later.
Even though my current method works, I'm positive there is a cleaner way of doing this rather than a query and 3 subqueries. I mainly want to learn how to better enhance my queries and minimizing the amount of them.
What I'm trying to do is
echo out all the data for each date with the date displayed on top
Display the count of entries for each user on that particular day next to the user
For each date, at the bottom of the above 2 bits of data, display the user/s with the highest number of entries
$query = mysql_query('SELECT * FROM entries GROUP BY DATE(dt)');
$g = 0;
while ($row = #mysql_fetch_array($query))
{
$group[$g] = date('y-m-d', strtotime($row['dt']));
echo $group[$g] . "<br />";
//display the person's name for today with their count
$dayquery = mysql_query('SELECT *, COUNT(username) as total FROM entries WHERE DATE(dt) = "'.$group[$g].'" GROUP BY username ORDER BY COUNT(username) DESC');
while ($today = #mysql_fetch_array($dayquery))
{
echo $today['first_name'] . " | " . $today['total'] . "<br />";
}
//display the highest count for today
$topquery = mysql_query('SELECT COUNT(username) as highest FROM entries WHERE DATE(dt) = "'.$group[$g].'" GROUP BY username ORDER BY COUNT(username) DESC LIMIT 1');
while ($toptoday = #mysql_fetch_array($topquery))
{
echo "Highest today: " . $toptoday['highest'] . "<br /><br />" ;
}
//display the users with the highest count for today
echo "Highest users: ";
$userstopquery = mysql_query('SELECT *, COUNT(username) as total FROM entries WHERE DATE(dt) = "'.$group[$g].'" AND COUNT(username) = "' . $toptoday['highest'] . '" AND GROUP BY username');
while ($topusers = #mysql_fetch_array($userstopquery))
{
echo $topusers['first_name'] . "<br />" ;
}
$g++;
}
The trouble I'm having is that when I try and reduce these subqueries and use MAX it will only output the highest count but not all the data for each date, which is what I need, including output of the user/s with the most amount of entries for that given day.

Answer 1

You could start with something like this. Note that I'm not using PHP's mysql_ API as it was deprecated 3 or 4 years ago...
require('path/to/mysqli/connection/stateme.nts');
$array = array();
$query = "
SELECT e.dt
, e.username
, COUNT(*) ttl
FROM entries e
GROUP
BY e.dt
, e.username
ORDER
BY e.dt, ttl DESC;
";
$result = mysqli_query($conn,$query);
while ($row = mysqli_fetch_assoc($result))
{
$array[] = $row;
}
print_r($array);