PHP MySQL get data from temporary column - php

Question

My situation:
I have a table ('players') that contains data about players. It has fields: name, surname, lv points, itf points and total points (auto-generated, lv points + itfpoints) and gender. The same table contains data about male and female.
What I want to do is to create a column or select temporary column "Rank" that will be based on total points.
Example:
| rank (temp_col) | name | totalpoints
| 1 | Nick | 199
| 2 | Rob | 190
| 3 | Alex | 155
| 4 | Max | 144
And then I want to get a data for a particular name, like
SELECT rank FROM players WHERE name = 'Nick'
I have separate page for each player and I want to show rank for each person.
My PHP code:
<?php
$sql = "SELECT *, (lvpoints + itfpoints) AS totalpoints FROM players WHERE club = 'TENNISJOY' ORDER BY gender DESC, totalpoints DESC";
$result = mysqli_query($conn, $sql);
$i = 0;
while($row = mysqli_fetch_assoc($result)){
$i += 1;
$name = $row['name'];
$surname = $row['surname'];
$gender = $row['gender'];
$sql2 = "SELECT *, (lvpoints + itfpoints) AS totalpoints FROM players WHERE gender = '$gender' AND name='$name' AND surname='$surname' ORDER BY totalpoints DESC";
$result2 = mysqli_query($conn, $sql2);
$row2 = mysqli_fetch_assoc($result2);
$points = $row2['totalpoints'];
$sql3 = "SELECT
(#cnt := #cnt + 1) AS rank,
surname, name, (lvpoints + itfpoints) AS totalpoints, lvpoints, itfpoints, club
FROM players
JOIN (SELECT #cnt := 0) AS dummy
WHERE gender='$gender'";
$result3 = mysqli_query($conn, $sql3);
$row3 = mysqli_fetch_assoc($result3);
$rank = $row3['rank'];
echo '
<div class="row">
<div class="col-md-4">
<div class="well dash-box">
<h4> ' . $i . '. ' . $surname . ' ' . $name. ' ('. $gender . ') '. '</h4>
<img src="img/noava.png" height="200px" width="200px" />
</div>
</a>
</div>
<div class="col-md-8">
<div class="well dash-box">
<h4 align="left">Player details</h4>
<p align="left">LV Rank : ' . $rank . '<br/><br/>
Total points : ' . $points .'<br/>
LV points : ' . $row['lvpoints'] . '<br/>
<br/>
ITF Rank : <br/>
ITF Points : ' . $row['itfpoints'] . '<br/>
</p>
</div>
</a>
</div>
</div>
';
}
?>
If you have any ideas how to implement it, give a shout, please!

Answer 1

Personally, I would do away with calculating rank on the fly. Instead you would want to calculate this and store it in the table, after modifying the data.
This will require way more code then I care to post right now, but the basic Idea is that when something changes. Say a player gets more "points" you would recalculate the rank for each player, then store that either in the same table, or in a separate but related one.
That way when it comes time to do the query, your data is all there and it's a trivial task to do.
The issue with how you are doing it now, is the data doesn't get saved and therefor you can't query against it later.
The only way to do it on the fly like this would be to filter through the result set of the first ( second ) query that creates that value. This would be prohibitive performance wise, because you would be pulling all players out and then sifting through them for the one you want using PHP.
It's better to front load the performance cost of doing calculations by recalculating this when the data in the table changes, and having a simple numeric value to work with.