Question

I am using GROUP BY to only select one row for all entries that share the same ‘cat_no’ value, because GROUP BY retrieves a random row I need to use ORDER BY ABS(track) to ensure it selects the row that is track number “1” in the database. However once I have this set of results I need to actually have the final order by ‘date’ another field in the DB, but I can’t seem to order twice.

SELECT * FROM cds  
WHERE genre='rock'  
GROUP BY cat_no  
ORDER BY date DESC,ABS(track) DESC  
LIMIT 0,3

Sql is only honouring the first order by clause, in this case ‘date’, if I swap them around then ‘track’ is used and ‘date’ ignored

Table

genre cat_no  track  date
rock  001     1      09323123
rock  001     2      09323123
rock  001     bundle 09323123
rock  002     1      09323123
rock  002     2      09323123
rock  002     bundle 09323123
rock  003     1      09323123
rock  003     2      09323123
rock  003     bundle 09323123

Answer 1

If you always want track 1, you don’t need to group:

SELECT * FROM cds
WHERE genre = 'rock' AND track = 1
ORDER BY date DESC
LIMIT 0, 3

If you want the first track (not necessarily track 1), then you need a subquery:

SELECT * FROM cds c
WHERE genre = 'rock'
AND track = (
    SELECT MIN(track) FROM cds innerq
    WHERE innerq.cat_no = c.cat_no
    LIMIT 1
)
ORDER BY date DESC
LIMIT 0, 3