Having written dozens of Perl DBI based scripts/apps/CGI/whatever over the years I'm pretty set in my ways of approaching things like this. So let me show you my method and see if it helps you. 

#!/usr/bin/perl -w 
#
# Boiler-plate-ish database pattern
use strict;
use DBI;

my $dbh = DBI->connect("DBI:Pg:dbname=mydatabase",'','')
         or die $DBD::errstr;

my $sth = $dbh->prepare(
qq(
SELECT Count(*) as x from e_annotation_090812.annotation A WHERE A.use
+r IN (SELECT T.Line FROM europhenome_annotation_090812.Temp_table T) 
+AND entity_name LIKE '%' AND evidence_code NOT LIKE ? AND A.centre LI
+KE ?
)               ) or die $dbh->errstr;

# Handwaving $ev_code and $pattern2
$sth->execute ("%" . $ev_code,"%" . $pattern2);

my ($count) = $sth->fetchrow_array();

[download]

Important elements of that code to consider.

  1. Use placeholders... you'll be glad you did. DBI takes care of making sure the correct quoting is in place. Prepending or appending the wildcard character works well.
  2. The prepare/execute sequence will save you some grief. Especially if you trap errors as I've shown in my example.
Hope this helps...

Peter L. Berghold -- Unix Professional
Peter -at- Berghold -dot- Net; AOL IM redcowdawg Yahoo IM: blue_cowdawg

In reply to Re: Perl DBI - returning a single value by blue_cowdawg
in thread Perl DBI - returning a single value by Freezer

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.