Hello Perl Monks, Hoping on your help in this "puzzle" :) I'm trying to calculate a sum of the numbers, which i get from DB table. I have 3 fields: "id", "side" and "cost". Mysql query output is the following: 
id side cost
------------
1 | A | 120
2 | B | 90
3 | C | 110
4 | C | 100
5 | B | 140
6 | A | 50
7 | C | 160
8 | B | 120
9 | A | 110

[download]
from this output i'm trying to find a summary of 2 rows with `cost` field. In `side` field first row should be the B, and second one should be the one, which i going next in the output right after B.

eg. B = 90 and next from the row(C) = 110, so sum should be 200. then next B = 140, and next row(A) = 50. sum = 190 and last B = 120, A = 110. sum = 230.

If someone will help me with this, it will be really appreciated. Thanks in advance!

In reply to summary of the numbers in some sequence by paul_van_eeren

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.