MySQL PHP select only non-duplicate entries in a field

Question

I have this SQL tableName:

dataId | projectId | keywords
-------|-----------|--------
1      |     1     | keyword 1, keyword 2, keyword 3, keyword 4, keyword 1
2      |     2     | keyword 5, keyword 6, keyword 7

Is it possible to SELECT dataId, projectId, keywords FROM tableName and echo non-duplicates in dataId 1, project 1 field?

The ideal output would be:

keyword 1, keyword 2, keyword 3, keyword 4

Not

keyword 1, keyword 2, keyword 3, keyword 4, keyword 1

Ideally you should restructure your table, having a list of keywords isn't ideal - as you've found out. — Nigel Ren, Jul 14 '20 at 07:31
Do it in PHP. Use `explode()` to turn the keywords into an array, then use `array_unique()` to remove duplices. — Barmar, Jul 14 '20 at 07:36
But that's only necessary until you fix the database design, as the others have said. — Barmar, Jul 14 '20 at 07:37

score 0 · Answer 1 · answered Jul 14 '20 at 07:37

To de-duplicate a comma-separated list of string, you can do this:

$keywords = 'keyword 1, keyword 2, keyword 3, keyword 4, keyword 1';
$dedup = implode(', ', array_unique(array_map('trim', explode(',', $keywords))));
echo $dedup;

Result:

keyword 1, keyword 2, keyword 3, keyword 4

You should probably do this before inserting to your database for performance. But it'll also work afterwards.

MySQL PHP select only non-duplicate entries in a field

1 Answers1