存储和处理MySQL结果

So, I'm learning PHP and MySQL, but I have run into a little problem here.

I do lack some information, so this will be very helpful to me =)

I do a query against my database, and get a result. This result is all my image files to be listed.

$fileSQL = $mysqli->query("
    SELECT *
    FROM content
    WHERE projID=$projectID     
");

So, if I want to list all my files as thumbnails on my page I do this:

<?php while($row = $fileSQL->fetch_assoc()){ ?>
    <img src="assets/<?=$row['contentFull']?>" id="thumbImg"
    onclick="document.getElementById('mainImage').src=this.src" width="110px" height="62px"/>           
<?php } ?>

Now, this works fine, of course. It loops through all the rows while adding a for each of them.

However, I do have a main image too, where I need to show the first thumb in full (for this example I use contentFull both for thumbs and fullsize).

Now, how do I get the first row's contentFull, without making the while loop start from row nr.2?

And in general; what is the best way to do in these situations? Store the result to an array first, so I can access it easily, or what is the "normal" way of doing it? =)

What I need:

Do a query
Set the main image (using contentFull from the first image/content in my sql result)
Then draw all the images in the result to thumbnails (including the first that are already shown as the main image)

Thanks in advance, and please let me know if you need more information =)

One simple options would be to do this:

<?php 
$first = null;
while($row = $fileSQL->fetch_assoc()) {
    if(!isset($first)) $first = $row;
    ?>
    <img src="assets/<?=$row['contentFull']?>" id="thumbImg"
    onclick="document.getElementById('mainImage').src=this.src" width="110px" height="62px"/>           
<?php } ?>

Now you have the first row stored in a variable to use, without having to store all the results in an array. If for some reason you want all rows stored in an array you could simply do this:

<?php 
$rows = array();
while($row = $fileSQL->fetch_assoc()) {
    $rows[] = $row;
    //rest of code
}
?>

Then you could access first row by referencing $rows[0]

Another option would be to not use php to populate the full image. Instead use a javascript call to populate the first image.

I think you could take your first picture outside the while loop:

$row = $fileSQL->fetch_assoc(); // the first picture
if($row){
  // show first image if it exists
  }

while ( $row = $fileSQL->fetch_assoc()) // etc.

Probably code for larger image is different than for others, so it could be reasonable. If not, consider defining a function, or use a counter (or flag like in Pitchinnate's answer).