chessworld

create function distance(lat1 real, lng1 real, lat2 real, lng2 real) returns real no sql
return ATAN2(SQRT(POW(COS(RADIANS(lat2)) * SIN(RADIANS(lng1 - lng2)), 2) + 
			POW(COS(RADIANS(lat1)) * SIN(RADIANS(lat2)) - SIN(RADIANS(lat1)) *
			COS(RADIANS(lat2)) *  COS(RADIANS(lng1 - lng2)), 2)), 
			(SIN(RADIANS(lat1)) * SIN(RADIANS(lat2)) + COS(RADIANS(lat1)) *
			COS(RADIANS(lat2)) * COS(RADIANS(lng1 - lng2)))) * 6372.795;