Question

Suppose i have a mysql table name table with fields

• rank
• date
• id

The values are like:

10, 2012-01-01, 3
9,  2012-01-04, 3
5,  2012-01-07, 3
3,  2012-01-10, 3
10, 2012-01-01, 4 
6,  2012-01-04, 4 
7,  2012-01-07, 4

In a single sql, how can i get both last and first values sorted by date grouped by id?

I know how to get first one or last one

SELECT rank, id FROM 
  (SELECT rank, id FROM table ORDER BY date DESC) s GROUP BY id;

I would like that the fields returned to be somethink like: lastrank, firstrank and id.

Thank you

Answer 1

Try this:

select id,
  max(if(MyOrder = 1, rank, null)) as FirstRank,
  max(if(MyOrder = 2, rank, null)) as LastRank
from (
    select t1.id, t1.rank, 1 MyOrder from t t1
    left join t t2 on
    t1.id = t2.id and t1.date > t2.date
    where t2.date is null
    union
    select t1.id, t1.rank, 2 from t t1
    left join t t2 on
    t1.id = t2.id and t1.date < t2.date
    where t2.date is null
) s
group by id

The result of this query taking your sampla data as input is:

+----+-----------+----------+
| ID | FIRSTRANK | LASTRANK |
+----+-----------+----------+
|  3 |        10 |        3 |
|  4 |        10 |        7 |
+----+-----------+----------+