#modern way
#
my $sortby = $cgi->param( 'sortby' ) // 'name';

# Perl5.8 way
#
my $sortby = $cgi->param( 'sortby' ) || 'name';

# If first value can be zero or empty string ..
#
my $sortby = ( defined $cgi->param( 'sortby' ) ? $cgi->param( 'sortby' )
             :                                   'name'
             );

# alternate arrangement
#
my $sortby = ( defined $cgi->param( 'sortby' ) 
             ? $cgi->param( 'sortby' )
             : 'name'
             );

##</code><code>##

my $variable = test1() ? value1
              : test2() ? value2
              : test3() ? value3
              :           default_value
              ;

##</code><code>##

use Readonly;
Readonly my %sql_defaults => ( sortby => 'name',
                               ascdesc => 'desc',
                               letter => q{ },
                              );
my %sql_args;
$sql_args{sortby}  = $cgi->param( 'sortby' )  || $sql_default{sortby};
$sql_args{ascdesc} = $cgi->param( 'ascdesc' ) || $sql_default{ascdesc};
$sql_args{letter}  = $cgi->param( 'letter' )  || $sql_default{letter};

# alternately, use a suffix 'for' to merge the three lines:
# 'qw()' does 'quote words'
#
$sql_args{$_} = $cgi->param( $_ ) || $sql_default{$_}
    for qw( sortby ascdesc letter );