php - MySQL 查询 - 替代方案

Question

我的查询太长(3-4 秒)。知道如何让它更快吗？

SELECT u.id AS id_uzytkownika,
       u.login,
       u.ranga,
       u.online_light AS online,

  (SELECT MAX(id)
   FROM uzytkownicy_zdjecia
   WHERE id_uzytkownika = u.id
     AND prywatna =0) AS id_fotki,

  (SELECT fotka
   FROM uzytkownicy_zdjecia
   WHERE id = id_fotki) AS fotka ,

  (SELECT srednia_ocen
   FROM uzytkownicy_zdjecia
   WHERE id = id_fotki) AS srednia_ocen,

  (SELECT ile_ocen
   FROM uzytkownicy_zdjecia
   WHERE id = id_fotki) AS ile_ocen
FROM uzytkownicy u
WHERE u.foto =1
  AND u.plec = "mezczyzna"
ORDER BY srednia_ocen DESC,
         ile_ocen DESC,
         id_fotki DESC LIMIT 42

Answer 1

您能否解释一下您的表结构以及该查询的含义？由于列名不是英文，大多数读者可能无法理解您在这里尝试执行的操作...

一般来说，看起来您对同一个表有很多嵌套的 SELECT - 这有什么特殊原因吗？