my @array_1 = ("\$Id_run_query=1", "\$name_run_query=xyz", "db_query_run_query=select * from meter where metetid=\$Id and metername=\$name");
my $query;
my %replace;

foreach(@array_1){
    if (m/^db_query_run_query=(.*)/i){
        $query = $1
    }
    elsif (/(\$\S+)_run_query=(.*)/) {
        $replace{$1} = $2;
    }
}
my $replace_re = join '|', map quotemeta, keys %replace;
$query =~ s/($replace_re)/$replace{$1}/ig;

print "===>$query\n";