<?php
$Sql="SELECT *, (3959 * acos(cos(radians(37)) * cos(radians(44)) * cos(radians(55) -    radians(-122)) + sin(radians(37)) * sin(radians(44))) as distance FROM TableName       HAVING distance < 25 ORDER BY distance LIMIT 0 , 20";
$result=mysql_query($Sql);

while ($row = mysql_fetch_array($result)){
   echo $row['Id'];
}

SELECT *, (
        3959 * acos(
                 cos(radians(37)) * cos(radians(44)) *
                 cos(radians(55) -  radians(-122)) +
                 sin(radians(37)) * sin(radians(44))
                )
       )
    as distance FROM TableName HAVING distance < 25 ORDER BY distance LIMIT 0 , 20

(3959 * acos(cos(radians(37)) * cos(radians(44)) * cos(radians(55) -    radians(-122)) + sin(radians(37)) * sin(radians(44))))