Question

I’ve this table:

id    value     ref
1       0        10000
2       5        11000
3       5        11100
4       2        11101
5       2        11102
6      10        12000
...    ...         ....

How can i achieve this:

ref    sum(value)
10000   14         <-- 5 + 5 + 2 + 2
11000   9          <-- 5 + 2 + 2
11100   4          <-- 2 + 2
12000   10         <-- and so on

I can’t decided if this desing is valid, it won’t work, or i’m missing something.

I don’t have any sql query to show to you guys.

Using regex, maybe? which i’d read about it, but not fully understand.

Any help would be greatly appreciated

Answer 1

This might work for you, after replacing contentsum with the real name of your table:

select rpad(main.prefix, 5, 0) as ref, sum(contentsum.value) as total
    from (select distinct trim(trailing '0' from ref) as prefix from contentsum) as main
    join contentsum on contentsum.ref like concat(main.prefix, '%')
    group by main.prefix
;

However, its totals don’t match yours. Instead, they match what I thought you were adding up when I first read the question.

Basically, the key is to JOIN the table to itself on some function of the ref values, grouping by the left-hand side, and summing over the right-hand side. The subquery condenses identical rows and reduces some code duplication, but isn’t strictly necessary if the ref values are all unique.