Displaying data from linked tables

[adwfun]

I have 2 tables named City and District in MySQL.
Table City fields : CityID, CityName
Table District fields : DistrictID, DistrictName, CityID

I linked District to City. When retrieving data from District Table, how could I display CityName instead of cityID ?

My codes as follow:
What's problem ?

<?php
include("connectdb.php");
$district=mysql_query("select * from District");
while ($result=mysql_fetch_array($district))
{
echo $result["DistrictID"]."<br>";
echo $result["Districtname"]."<br>";
echo $result["select Districtname, Cityname from District, City where City.CityID=District.CityID"]."<br>";
}
?>

[fenway]

You're not actually issuing that query.