ทำไมเวลาดึงค่าใน sql แล้วไม่แสดงผลทั้งที่มีข้อมูลอยู่

SELECT * 
FROM `bskinpricktestfood` 
WHERE `allergens` = 'Histamine'
AND `wheal1` = '0'
AND `wheal2` = '0'
AND `flare1` = '0'
AND `flare2` = '0'
AND `allergens` = 'Egg yolk'

SELECT * 
FROM `bskinpricktestfood` 
WHERE
(`allergens` = 'Histamine' OR `allergens` = 'Egg yolk')
AND `wheal1` = '0'
AND `wheal2` = '0'
AND `flare1` = '0'
AND `flare2` = '0'

SELECT `HN` 
FROM `bskinpricktestfood` 
WHERE
(`allergens` = 'Histamine' OR `allergens` = 'Egg yolk')
AND `wheal1` = '0'
AND `wheal2` = '0'
AND `flare1` = '0'
AND `flare2` = '0'
GROUP BY `HN`