SQL for summing only new values

Question

Hi, i have a table like this

NAME    VALUE
-----------------
bla      1
bla      2
bla      2
bla      3
bla      1
bla      4
bla      2

How can i do a sum of ONLY different values , and ignore the repeating values (is it possible?)? Something like this :

 SELECT SUM(??condition?? value) as total FROM table

And the sum should be 10.

Thank you!

Answer 1

This should work:

SELECT SUM(value) as total FROM (SELECT DISTINCT value FROM table) tmp;

Source: http://forums.mysql.com/read.php?97,203188,203787#msg-203787

SELECT SUM(DISTINCT value) as total FROM table

Source: http://dev.mysql.com/doc/refman/5.1/en/group-by-functions.html#function_sum

The second solution is better because it does not create temporary table. Therefore it is faster.

Answer 2

Wouldn't

SELECT SUM(DISTINCT value) FROM mytable;

do the trick?

Answer 3

If you want to sum all distinct values then you can use DISTINCT:

SELECT SUM(DISTINCT value) AS total FROM yourtable

If you want to calculate a different sum for each name then add GROUP BY:

SELECT name, SUM(DISTINCT value) AS total 
FROM yourtable
GROUP BY name

Or to only consider a specific name:

SELECT SUM(DISTINCT value) AS total 
FROM yourtable
WHERE name = 'bla'