Remove duplicate comma separated values from mysql

Question

How can I remove duplicate comma separated values returned from database?

I have it in this format:

XL,L,XXL
XL
M,L,XL
L,XL,M

What I tried:

$new_str = array_unique(array_map('trim', explode(',', $srow['size'])));
$string = implode(',', $new_str);

But I still get duplicate values. Is there a better way of doing it?

you split them all first with comma and put each piece inside the container, in the end you use trim and array unique. don't do it by row, let the fetching finish first while gathering inside the container — Kevin, Mar 16 '20 at 03:00
@danblack, didn't get what you meant by removing it from database query. — Fagbemi Ayodele, Mar 16 '20 at 03:04
dan means instead of doing the unique in PHP layer, do it in mysql. should be easier if they aren't saved delimited — Kevin, Mar 16 '20 at 03:08
Are the values in the database stored in comma separated lists? — Nick, Mar 16 '20 at 03:09

score 5 · Accepted Answer · answered Mar 16 '20 at 03:18

Since your data is stored as comma separated values in the database, you will need to aggregate all the values as you loop over fetching from the database and then remove duplicates e.g.

while ($srow = $result->fetch_assoc()) {
    $sizes[] = $srow['size'];
    // do other stuff with fetched data
    // ...
}
$sizes = array_unique(array_map('trim', explode(',', implode(',', $sizes))));
sort($sizes);
$string = implode(',', $sizes);

Demo on 3v4l.org (with simulated database fetch)

Thanks a million times. I really appreciate it. It worked. Thanks again. — Fagbemi Ayodele, Mar 16 '20 at 03:23

Remove duplicate comma separated values from mysql

1 Answers1