Using php to compare mysql results, then echo differences? - php

Question

I'm new to PHP and I'm trying to figure out how I can compare two mysql query results and echo out the differences. Basically I have a database that is comparing state flag characteristics. The user would select 2 states and what I would like is to have the php echo out 3 sets of results (state 1 only, shared characterisics, and state 2 only). My rough code below only echos out characteristics for states 1 and 2. Is there a way that I can compare the query results, so that I get differences between the states, and also shared characteristics.
<?php $query1 = $_GET['query1'];
$query2 = $_GET['query2'];
$min_length = 2;?>
<!-- state 1 characteristics only -->
<div class="fluid s1charc">
<?php echo "<strong><p>Search results for $query1</strong></p>";?>
<?php if(strlen($query1) >= $min_length){$query1 = htmlspecialchars($query1);
$query1 = mysql_real_escape_string($query1);
$raw_results1 = mysql_query("SELECT * FROM charc_s WHERE `charc_f` ='$query1' ORDER BY FLAG_S") or die(mysql_error());
if(mysql_num_rows($raw_results1) > 0) {
while($results1 = mysql_fetch_array($raw_results1)){
echo "<table id='iseqchart' class='sortable'>
<tr valign='middle'>
<td ><a href='flag.php?FLAG_ID=".$results1['FLAG_ID']."'><img src='images/".$results1['IMAGE']."'></a></td>
<td> </td>
<td><strong><font size='3'><a href='flag.php?FLAG_ID=".$results1['FLAG_ID']."' style='color:#100783'>".$results1['FLAG_S']." (".$results1['STATE'].")</strong></a>
</td>
</tr>
</table>";
}
}
else{ // if there is no matching rows do following
echo "No results were found";
}
}
else{ // if query length is less than minimum
echo " ".$min_length;
}
?>
</div>
<!-- shared characteristics -->
<div class="fluid sharecharc">Shared</div>
<!-- state 2 characteristics only -->
<div class="fluid s2charc">
<?php echo "<strong><p>Search results for $query2</strong></p>"; ?>
<?php if(strlen($query2) >= $min_length){$query2 = htmlspecialchars($query2);
$query2 = mysql_real_escape_string($query2);
$raw_results = mysql_query("SELECT * FROM charc_s WHERE `charc_f` ='$query2' ORDER BY FLAG_S") or die(mysql_error());
if(mysql_num_rows($raw_results) > 0) {
while($results = mysql_fetch_array($raw_results)){
echo "<table id='iseqchart' class='sortable'>
<tr valign='middle'>
<td ><a href='flag.php?FLAG_ID=".$results['FLAG_ID']."'><img src='images/".$results['IMAGE']."'></a></td>
<td> </td>
<td><strong><font size='3'><a href='flag.php?FLAG_ID=".$results['FLAG_ID']."' style='color:#100783'>".$results['FLAG_S']." (".$results['STATE'].")</strong></a>
</td>
</tr>
</table>";
}
}
else{ // if there is no matching rows do following
echo "No results were found";
}
}
else{ // if query length is less than minimum
echo " ".$min_length;
}
?>
</div>

Answer 1

The best way to do this is on the server side. Make the database do 3 different selects. The reason is that the server will run the queries a lot faster than the php. And it will end up in a better user experience.
Only Table A
SELECT * FROM TableA A LEFT JOIN TableB B ON A.key = B.key
Only Table B
SELECT * FROM TableA A RIGHT JOIN TableB B ON A.key = B.key
And in Both Tables
SELECT * FROM TableA A INNER JOIN TableB B ON A.key = B.key
From there echo out your results.