set @lat= x; //hardcoded latitude value
set @lng= y; //hardcoded longitude value

SELECT *
FROM police_station
ORDER BY ((police_station_lat - @lat)*(police_station_lat - @lat)) +
((police_station_lng - @lng)*(police_station_lng - @lng)) ASC
LIMIT 1;

+------------------+------------------------+-------------------------+--------------------+
 |police_station_id |police_station_latitude |police_station_longitude |police_station_name |
 +------------------+------------------------+-------------------------+--------------------+
 |               17 |              53.289543 |                 -6.2426 | Dundrum            |
 +------------------+------------------------+-------------------------+--------------------+

/*
 * Google Map with marker
 */
function initialize() {
    var initialLat = $('.search_latitude').val();
    var initialLong = $('.search_longitude').val();
    initialLat = initialLat?initialLat:53.350140;
    initialLong = initialLong?initialLong:-6.266155;

    var latlng = new google.maps.LatLng(initialLat, initialLong);
    var options = {
        zoom: 11,
        center: latlng,
        mapTypeId: google.maps.MapTypeId.ROADMAP
    };

    map = new google.maps.Map(document.getElementById("geomap"), options);

    geocoder = new google.maps.Geocoder();

    marker = new google.maps.Marker({
        map: map,
        draggable: true,
        position: latlng
    });

    google.maps.event.addListener(marker, "dragend", function () {
        var point = marker.getPosition();
        map.panTo(point);
        geocoder.geocode({'latLng': marker.getPosition()}, function (results, status) {
            if (status == google.maps.GeocoderStatus.OK) {
                map.setCenter(results[0].geometry.location);
                marker.setPosition(results[0].geometry.location);
                $('.search_addr').val(results[0].formatted_address);
                $('.search_latitude').val(marker.getPosition().lat());
                $('.search_longitude').val(marker.getPosition().lng());
            }
        });
    });

}

$(document).ready(function () {
    //load google map
    initialize();

    /*
     * autocomplete location search
     */
    var PostCodeid = '#search_location';
    $(function () {
        $(PostCodeid).autocomplete({
            source: function (request, response) {
                geocoder.geocode({
                    'address': request.term
                }, function (results, status) {
                    response($.map(results, function (item) {
                        return {
                            label: item.formatted_address,
                            value: item.formatted_address,
                            lat: item.geometry.location.lat(),
                            lon: item.geometry.location.lng()
                        };
                    }));
                });
            },
            select: function (event, ui) {
                $('.search_addr').val(ui.item.value);
                $('.search_latitude').val(ui.item.lat);
                $('.search_longitude').val(ui.item.lon);
                var latlng = new google.maps.LatLng(ui.item.lat, ui.item.lon);
                marker.setPosition(latlng);
                initialize();
            }
        });
    });

    /*
     * Point location on google map
     */
    $('.get_map').click(function (e) {
        var address = $(PostCodeid).val();
        geocoder.geocode({'address': address}, function (results, status) {
            if (status == google.maps.GeocoderStatus.OK) {
                map.setCenter(results[0].geometry.location);
                marker.setPosition(results[0].geometry.location);
                $('.search_addr').val(results[0].formatted_address);
                $('.search_latitude').val(marker.getPosition().lat());
                $('.search_longitude').val(marker.getPosition().lng());
            } else {
                alert("Geocode was not successful for the following reason: " + status);
            }
        });
        e.preventDefault();
    });

    //Add listener to marker for reverse geocoding
    google.maps.event.addListener(marker, 'drag', function () {
        geocoder.geocode({'latLng': marker.getPosition()}, function (results, status) {
            if (status == google.maps.GeocoderStatus.OK) {
                if (results[0]) {
                    $('.search_addr').val(results[0].formatted_address);
                    $('.search_latitude').val(marker.getPosition().lat());
                    $('.search_longitude').val(marker.getPosition().lng());
                }
            }
        });
    });
});