Topic: DISTINCT or GROUP BY

[Which is best to use when extracting one column, DISTINCT or GROUP BY?]

Which is best to use when extracting one column, DISTINCT or GROUP BY?

Distinct

 1 (20%)

Group by

 1 (20%)

No difference

 3 (60%)

Total Members Voted: 5

[sphinx9999]

Which do you think is better, DISTINCT or GROUP BY?

Code: [Select]

SELECT DISTINCT id FROM phrase WHERE campaign LIKE 'proper%'
or

Code: [Select]

SELECT id FROM phrase WHERE campaign LIKE 'proper%' GROUP BY advert_id
I've asked this question before and received the following answer from a reliable source: "When there's just one column it doesn't matter". Do you agree?

[Daniel0]

It depends on what you're trying to do.

[aschk]

GROUP BY

[jaymc]

Benchmark it ;-)

phpmyadmin is good, it tells you time taken to execute a query

[freenity]

I know old topic, but have a look at this: http://gwphp.feudal-times.net/?p=5
benchmarked and everything

Guess who wins

[fenway]

This is mainly because distinct is a filesort operation which group by has the chance to use an index or some temporary filesorting on smaller sets along the way.

[goldfiles]

Group By usually

[abs0lut]

i will not use distinct anymore