Find all records in database that are within a certain distance of a set of lat and long points
- by Mike L
I've seen all the examples and here's what I got so far.
my table is simple:
schools (table name)
- School_ID
- lat
- long
- county
- extrainfo
here's my code:
<?php
$con = mysql_connect("xxx","xxx","xxx");
if (!$con) {
die('Could not connect: ' . mysql_error());
} else {}
mysql_select_db("xxx", $con);
$latitude = "36.265541";
$longitude = "-119.207153";
$distance = "1"; //miles
$qry = "SELECT *, (3958.75 * ACOS(SIN(" . $latitude . " / 57.2958)*SIN(lat / 57.2958)+COS(" . $latitude . " / 57.2958)*COS(lat / 57.2958)*COS(long / 57.2958 - " . $longitude . " / 57.2958))) as distance FROM schools WHERE (3958.75 * ACOS(SIN(" . $latitude . " / 57.2958)*SIN(lat / 57.2958)+COS(" . $latitude . " / 57.2958)*COS(lat / 57.2958)*COS(long / 57.2958 - " . $longitude . " / 57.2958))) <= " . $distance;
$results = mysql_query($qry);
if (mysql_num_rows($results) > 0) {
while($row = mysql_fetch_assoc($results)) {
print_r($row);
}
} else {}
mysql_close($con);
?>
but I get this error when I try to run it:
Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource
