SELECT col1 FROM table WHERE condition;
    if (col1 exists) {
        UPDATE table SET col2 = <new value>
    }

##</code><code>##

    PerlModule Apache::DBI

##</code><code>##

    <Location />
        SetHandler perl-script
        PerlHandler Plack::Handler::Apache2
        PerlSetVar psgi_app /path/to/application.pl
    </Location>