SQL query taking “too” long - select with distinct and max

Question

I have the scenario:

A table with POSITION and a value associated for each position, BUT I have always 4 values for the same position, so an example of my table is:

position | x| values 
1 | x1 | 0
1 | x2 | 1
1 | x3 | 1.4
1 | x4 | 2
2 | x1 | 3
2 | x2 | 10
2 | x3 | 12.4
2 | x4 | 22

I need a query that returns me the MAX value for each unique position value. Now, I am querying it with:

SELECT DISTINCT (position) AS p, (SELECT MAX(values) AS v FROM MYTABLE  WHERE position = p) FROM MYTABLE;

It took me 1651 rows in set (39.93 sec), and 1651 rows is just a test for this database (it probably should have more then 1651 rows.

What am I doing wrong ? are there any better way to get it in a faster way ?

Any help is appreciated. Cheers.,

Answer 1

Use the GroupBy-Clause:

SELECT Position, MAX(VALUES) FROM TableName
GROUP BY Position

Also, have a look at the documentation (about groupby): http://dev.mysql.com/doc/refman/5.0/en/group-by-functions.html

Answer 2

Try using the GROUP BY clause:

SELECT position AS p, MAX(values) AS v
FROM MYTABLE
GROUP BY p;

Answer 3

try this

 SELECT position AS p, MAX(`values`) AS v FROM MYTABLE 
 GROUP BY position 

DEMO HERE

OUTPUT:

    P | V
    1 | 2
    2 | 22