mysql prevent duplicate rows, if field is repeated

Question

Can I, and if so, how do I prevent mysql from returning duplicate results

 SELECT meta_id, post_id, DISTINCT meta_value FROM wp_postmeta WHERE post_id='69' AND meta_value LIKE '%iframe%'

I want to get just the one row, so ignore any further items if meta_value duplicated!

Putting DISTINCT where it is, returns no results, but query works as expected if removed, so it is obviously wrong to put it there!

SELECT meta_id, post_id,meta_value FROM wp_postmeta WHERE post_id='69' AND meta_value LIKE '%iframe%' GROUP BY meta_value — laiju
– laiju, Commented Nov 30, 2017 at 10:07

Kapil Bhatt · Accepted Answer · 2017-11-30 11:14:05Z

1

If you want only one result you can use LIMIT in MySql like

SELECT meta_id, post_id, DISTINCT meta_value 
FROM wp_postmeta 
WHERE post_id='69' 
AND meta_value LIKE '%iframe%'
LIMIT 1

OR in Sql you can use

SELECT TOP 1 meta_id, post_id, DISTINCT meta_value 
FROM wp_postmeta 
WHERE post_id='69' 
AND meta_value LIKE '%iframe%'

answered Nov 30, 2017 at 10:37

Kapil Bhatt

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2 Comments

Good idea, but I need it to return a unique set, meta_value seems to have duplicates for some reason!

Then I think you can go with the GROUP BY meta_value as suggested by @laiju in the previous comment.