Select ONLY one row per category

Question

Ok I have siple table which contains data:

id  cat_id  title  (with random values)

1    1       test  
2    1       tstt              
3    3       tewt           
4    2       4324            
5    3       rterter  

Now, I need to create a query which selects only ONE raw per category (cat_id) (possibly with lowest ID and ordered by cat_id)

So the result should be:

1    1     test                  
4    2     4324                              
3    3     tewt                   

Answer 1

SELECT  a.*
FROM    tableName a
        INNER JOIN
        (
            SELECT  cat_id, MIN(id) id
            FROM    tableName
            GROUP   BY cat_id
        ) b ON a.cat_id = b.cat_id AND
                a.id = b.id
ORDER   BY a.cat_id

Answer 2

Use GROUP BY :

SELECT MIN(id), cat_id, title FROM table GROUP BY cat_id