SELECT id, ort, fachwort, (
6368 * SQRT(2*(1-cos(RADIANS(lng)) *
cos(0.20495444405846) * (sin(RADIANS(lat)) *
sin(0.83107429026474) + cos(RADIANS(lat)) *
cos(0.83107429026474)) - sin(RADIANS(lng)) * sin(0.20495444405846)))) AS entfernung
FROM literatur WHERE
6368 * SQRT(2*(1-cos(RADIANS(lng)) *
cos(0.20495444405846) * (sin(RADIANS(lat)) *
sin(0.83107429026474) + cos(RADIANS(lat)) *
cos(0.83107429026474)) - sin(RADIANS(lng)) * sin(0.20495444405846))) <= 25
ORDER BY entfernung