Пребройте непразните полета mysql

Вашият код се опитва да преброи броя на редовете, където всички полета не са нулеви. Трябва да използвате is not null вместо просто not null .

За да преброите броя на полетата, използвайте това:

SELECT sum((listing_photo_1 IS NOT NULL) +
           (listing_photo_2 IS NOT NULL) +
           (listing_photo_3 IS NOT NULL) +
           (listing_photo_4 IS NOT NULL) +
           (listing_photo_5 IS NOT NULL) +
           (listing_photo_6 IS NOT NULL) +
           (listing_photo_7 IS NOT NULL) +
           (listing_photo_8 IS NOT NULL)
          ) as total
from listings
WHERE pmpid = '$pmpid';

За да преброите броя на редовете:

SELECT count(*) as total
from listings
WHERE listing_photo_1 IS NOT NULL AND
      listing_photo_2 IS NOT NULL AND 
      listing_photo_3 IS NOT NULL AND 
      listing_photo_4 IS NOT NULL AND 
      listing_photo_5 IS NOT NULL AND 
      listing_photo_6 IS NOT NULL AND 
      listing_photo_7 IS NOT NULL AND 
      listing_photo_8 IS NOT NULL AND 
      pmpid = '$pmpid'";

РЕДАКТИРАНЕ:

Ако са празни, използвайте логиката по следния начин:

SELECT sum((listing_photo_1 IS NOT NULL and listing_photo_1 <> '') +
           (listing_photo_2 IS NOT NULL and listing_photo_2 <> '') +
           (listing_photo_3 IS NOT NULL and listing_photo_3 <> '') +
           (listing_photo_4 IS NOT NULL and listing_photo_4 <> '') +
           (listing_photo_5 IS NOT NULL and listing_photo_5 <> '') +
           (listing_photo_6 IS NOT NULL and listing_photo_6 <> '') +
           (listing_photo_7 IS NOT NULL and listing_photo_7 <> '') +
           (listing_photo_8 IS NOT NULL and listing_photo_8 <> '')
          ) as total
from listings
WHERE pmpid = '$pmpid';