Qo‘llanma · SQL
group-by
7 ta masala Masalalar ro‘yxatida
Nazariya
GROUP BY qatorlarni bir xil qiymat bo‘yicha guruhlarga bo‘ladi; agregat funksiya har guruh uchun hisoblanadi.
SELECT city, COUNT(*) AS n
FROM students
GROUP BY city
ORDER BY n DESC;
SELECT faculty, ROUND(AVG(grade), 2) AS avg_grade
FROM students
GROUP BY faculty;
Qoida
SELECT dagi har bir oddiy (agregat bo‘lmagan) ustun GROUP BY da ham bo‘lishi kerak.
Bajarilish tartibi: FROM → WHERE → GROUP BY → HAVING → SELECT → ORDER BY → LIMIT.
Easy
- Easy
- Easy
- Easy
- Easy
- Easy
Medium
- Medium
- Medium