Problem with php array to sort two db fields

I am stuck creating an array to merge to db fields together. The two strings are compared and if the same entries are found, then only one should display.

code:
if ($list_item == $countryC)
//echo "$list_item ($num)
";
{

while (array_unique($list_item, $countryC));

echo "$list_item ($num)
";
}
else
{
echo "$list_item
";

This doesn't work, but hopefully, you can see what i'm trying to do.

Thanks