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 );