PHP Change MySQL Order By If Condition Met - php

Question

I'm trying to change the order of MySQL results depending on if an if condition is met in PHP.
My code checks to see if any rows are duplicates and changes the row class if it is.
What I'm trying to achieve is if there is a duplicate then the MySQL query is ordered by Frequency and if there are no duplicates found then order it by Name.
This is what I have:
function getFrequencies() {
$conn = getConnected("websiteData");
$frequencyQuery = "
SELECT
f.Name,
f.Frequency,
f.Country,
f.Programmed,
(SELECT count(*) FROM frequencies WHERE Frequency = f.Frequency) as count
FROM frequencies f;
";
$frequencyResult = mysqli_query($conn, $frequencyQuery);
while ($frequencyRow = mysqli_fetch_assoc($frequencyResult)) {
if($frequencyRow['count'] > 1) {
$frequencyQuery = "
SELECT
f.Name,
f.Frequency,
f.Country,
f.Programmed,
(SELECT count(*) FROM frequencies WHERE Frequency = f.Frequency) as count
FROM frequencies f
ORDER BY Frequency;
";
} else {
$frequencyQuery = "
SELECT
Name,
Frequency,
Country,
Programmed
FROM frequencies
ORDER BY Name;
";
}
}
$frequencyResult = mysqli_query($conn, $frequencyQuery);
while ($frequencyRow = mysqli_fetch_assoc($frequencyResult)){
if ($frequencyRow['count'] > 1) {
echo '<tr class="warning">' .
"<td>" . $frequencyRow['Name'] . "</td>" .
"<td>" . $frequencyRow['Frequency'] . "</td>" .
"<td>" . $frequencyRow['Country'] . "</td>" .
"<td>" . $frequencyRow['Programmed'] . "</td>" .
"</tr>" . PHP_EOL;
} else {
echo "<tr>" . PHP_EOL .
"<td>" . $frequencyRow['Name'] . "</td>" .
"<td>" . $frequencyRow['Frequency'] . "</td>" .
"<td>" . $frequencyRow['Country'] . "</td>" .
"<td>" . $frequencyRow['Programmed'] . "</td>" .
"</tr>" . PHP_EOL;
}
}
}
Now I know for a fact that my table contains duplicates but currently there aren't any highlighted rows and the order is by Name.
Before I changed my code to the above stated one it was this one which did highlight my duplicate rows:
function getFrequencies() {
$conn = getConnected("websiteData");
// $frequencyQuery = "SELECT Name, Frequency, Country, Programmed, count(*) FROM frequencies GROUP BY Frequency ORDER BY Name";
$frequencyQuery = "
SELECT
f.Name,
f.Frequency,
f.Country,
f.Programmed,
( SELECT count(*) FROM frequencies WHERE Frequency = f.Frequency ) as count
FROM frequencies f
ORDER BY Frequency;
";
$frequencyResult = mysqli_query($conn, $frequencyQuery);
while ($frequencyRow = mysqli_fetch_assoc($frequencyResult)) {
if ($frequencyRow['count'] > 1) {
echo '<tr class="danger">' . PHP_EOL .
"<td>" . $frequencyRow['Name'] . "</td>" . PHP_EOL .
"<td>" . $frequencyRow['Frequency'] . "</td>" . PHP_EOL .
"<td>" . $frequencyRow['Country'] . "</td>" . PHP_EOL .
"<td>" . $frequencyRow['Programmed'] . "</td>" . PHP_EOL .
"</tr>" . PHP_EOL;
} else {
echo "<tr>" . PHP_EOL .
"<td>" . $frequencyRow['Name'] . "</td>" . PHP_EOL .
"<td>" . $frequencyRow['Frequency'] . "</td>" . PHP_EOL .
"<td>" . $frequencyRow['Country'] . "</td>" . PHP_EOL .
"<td>" . $frequencyRow['Programmed'] . "</td>" . PHP_EOL .
"</tr>" . PHP_EOL;
}
}
}
What can I do to achieve what I am trying to do? The reason I want to change the order is because when there are no duplicates it is a preference to scroll through the list alphabetically, but if there are duplicates then ordering it by Frequency puts the duplicates one row after the other making it easy to find and edit/delete.

Answer 1

Based on what you're trying to do I would build an Associative Array of the results and then use your logic to order them using PHP instead of MySQL's order by clause.
A method you could take (if you want to retain all duplicates) would be to build the table by sorting the array by the Name key and then saying if unique display else for each duplicate in array display which will result in all of the duplicates being displayed in succession, with the entire thing sorted by Name alphabetically, you can use asort for this.
In order to stop this from triggering side effects you could build two arrays, one from the MySQL select and one that is unique using array_unique that way when you loop through the array to display the page you can loop through the unique array and only grab the duplicate elements from the original array when rendering.
Consider the following:
<?php
$array = array();
$uniqueArray = array_unique($array);
for ( $i = 0; $i < sizeof($uniqueArray); ++$i ) {
if ( in_array($uniqueArray[$i], $array) ) {
// Item has duplicates
} else {
// item is unique
}
}
?>
If you don't want to retain duplicates you can quite simply follow the same formula but upon matching a duplicate instead of displaying them you can purge each of them from the database only retaining one then render the item from the unique array.