Question

I just want to ask how can the order by clause be performed first before the actual select statement.

I have query under PHP:

mysql_query("SELECT  GROUP_CONCAT(sample_lang) AS locations 
             FROM postflight 
             WHERE rno='$cc' 
             ORDER BY sfno ASC") or die(mysql_error());

What the query does is to concat the values first before sorting it. What I want is to sort it by ascending first before concatting it. Any help will be appreciated. Thanks a lot!

Answer 1

You can use ORDER BY inside GROUP_CONCAT() function, try

SELECT GROUP_CONCAT(sample_lang ORDER BY sfno ASC)
FROM ...
WHERE ...

or if you want to add SEPARATOR

SELECT GROUP_CONCAT(sample_lang ORDER BY sfno ASC SEPARATOR '-')
FROM ...
WHERE ...

SQLFiddle Demo