Beefy Boxes and Bandwidth Generously Provided by pair Networks
Syntactic Confectionery Delight

Comment on

( #3333=superdoc: print w/ replies, xml ) Need Help??
Ok - I'm interested now. I'm going to assume that the following is the table definition:
CREATE TABLE `test` ( `id` INT NOT NULL AUTO_INCREMENT PRIMARY KEY ,`brand` VARCHAR(255) NOT NULL ,`date` DATE NOT NULL ,INDEX (`brand`,`date`) ,INDEX (`date`,`brand`) );
Given that, you can do something assuming that the number of reads is at least 20x the number of writes (otherwise it's really not that performant). Basically, the idea is to maintain the `rank` column on each INSERT, UPDATE, or DELETE. Your writes get slow, but your reads get fast. This, essentially, is a cache. You can do this maintenance either in code or using a trigger. MySQL has triggers, so that works out nicely.

My criteria for good software:
  1. Does it work?
  2. Can someone else come in, make a change, and be reasonably certain no bugs were introduced?

In reply to Re^5: find difference in dates/items in same column by dragonchild
in thread find difference in dates/items in same column by zerocred

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, 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, 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.
  • Log In?

    What's my password?
    Create A New User
    and the web crawler heard nothing...

    How do I use this? | Other CB clients
    Other Users?
    Others musing on the Monastery: (13)
    As of 2015-11-30 20:38 GMT
    Find Nodes?
      Voting Booth?

      What would be the most significant thing to happen if a rope (or wire) tied the Earth and the Moon together?

      Results (782 votes), past polls