mysqli SUM and MAX results - mysql

Question

hi guys im having trouble understanding how to get a MAX() and a SUM() from a Database
my database have 3 colums id - stuff - score looks like this
id-stuf-score
1-1-2
1-1-3
1-2-1
1-2-3
1-3-1
1-3-3
i need to make a
MAX(score) where stuff=1 and id = 1
MAX(score) where stuff=2 and id = 1
MAX(score) where stuff=3 and id = 1
.
.
etc
and then a
SUM(score) all the MAX(score)
i have hundred of rows and i cant think of a way to make it happens

Answer 1

make subquery table derivatives for each thing you need the max of, then add them all together.
SELECT SUM(a.max+b.max+c.max) as total
FROM (
(
SELECT MAX(score) as max
FROM tablename
WHERE stuff = 1 AND id = 1
) as a,
(
SELECT MAX(score) as max
FROM tablename
WHERE stuff = 2 AND id = 1
) as b,
(
SELECT MAX(score) as max
FROM tablename
WHERE stuff = 3 AND id = 1
) as c
);
Output:
_____________
| total |
+-----------+
| 12345 |
+-----------+

Answer 2

Try using group by to get your max scores, then sum the results.
Records in Table
I added a few more records to so the max(score) wouldn't be the same for every stuf.
mysql> select * from stuff;
+------+------+-------+
| id | stuf | score |
+------+------+-------+
| 1 | 1 | 2 |
| 1 | 1 | 3 |
| 1 | 2 | 1 |
| 1 | 2 | 3 |
| 1 | 3 | 1 |
| 1 | 3 | 3 |
| 1 | 3 | 4 |
| 1 | 3 | 1 |
| 1 | 2 | 5 |
| 1 | 2 | 1 |
+------+------+-------+
10 rows in set (0.00 sec)
Group By
mysql> select id, max(score) as max_score from stuff group by stuf;
+------+-----------+
| id | max_score |
+------+-----------+
| 1 | 3 |
| 1 | 5 |
| 1 | 4 |
+------+-----------+
3 rows in set (0.00 sec)
Sum It Up
mysql> select sum(max_score) from (select id, max(score) as max_score
from stuff group by stuf) sum_me;
+----------------+
| sum(max_score) |
+----------------+
| 12 |
+----------------+
1 row in set (0.00 sec)
One Note
Keep in mind that if you have more ids then you will need to limit your query to whichever id you are interested in or appropriately group the last query.
mysql> select id, sum(max_score) from (select id, max(score) as max_score
from stuff group by id, stuf) sum_me group by id;

Answer 3

you can try this
SELECT SUM(a.max) as total
FROM (
(
SELECT MAX(score) as max
FROM tablename
GROUP BY stuf, id
) as a
);