Please show the full query. It may be possible to modify the query, itself, to do what you ask.

If modifying the query to do all the work isn't possible, and presuming service_id is the route number, I would loop through the data, filling an array indexed by service_id. When the distance is less than the existing distance, replace it with the distance just read. Filling in your while loop with some guaranteed-to-look-like-code pseudo-code: 

my @stop_list;
my @distance;
while($sth -> fetch()){
    if((not defined($distance[$service]) or
       $distance[$service] > $distance) {

         $stop_list[$service] = $stops;
         $distance[$service] = $distance;
     }
}
foreach $service (@stop_list) {
   print "Stop: $stop_list[$service] distance: $distance[$service]\n"
}

[download]
Note that this is absolutely untested; it's pseudo-code.

This will set $stop_list[$service] to the appropriate stop number and $distance[$service] to the appropriate $stops and $distance, respectively, if the current value of $distance[$service] is undefined or greater than the distance just returned by the fetch.

corrected markup

emc

Any New York City or Connecticut area jobs? I'm currently unemployed.

There are some enterprises in which a careful disorderliness is the true method.

—Herman Melville

In reply to Re: Help with manipulating data from a database?? by swampyankee
in thread Help with manipulating data from a database?? by Harch84

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.