SELECT id, ort, fachwort, (
6368 * SQRT(2*(1-cos(RADIANS(lng)) *
cos(0.21591818226638) * (sin(RADIANS(lat)) *
sin(0.83536865958986) + cos(RADIANS(lat)) *
cos(0.83536865958986)) - sin(RADIANS(lng)) * sin(0.21591818226638)))) AS entfernung
FROM literatur WHERE
6368 * SQRT(2*(1-cos(RADIANS(lng)) *
cos(0.21591818226638) * (sin(RADIANS(lat)) *
sin(0.83536865958986) + cos(RADIANS(lat)) *
cos(0.83536865958986)) - sin(RADIANS(lng)) * sin(0.21591818226638))) <= 25
ORDER BY entfernung