SELECT DISTINCT buyrug'i

SELECT DISTINCT buyrug'idan, bir-biriga o'xshash bo'lmagan, ya'ni unikal qiymatlarni olish uchun foydalaniladi.Jadval, ustun ichida ko'pincha takroriy qiymatlar qamrab olingan bo'ladi; va ba'zida siz faqatgina o'xshash bo'lmagan qiymatlarni ro'yhatini olishni istashingiz mumkin.

SELECT DISTINCT sintaksis

SELECT DISTINCT ustun1, ustun2, ...
FROM jadval_nomi;

Quyida, "Murad Buildings" namuna uchun keltirilgan ma'lumot bazasidagi chet ellik "Xaridorlar" jadvalidan tanlanma ro'yhati keltirilgan:

CustomerID CustomerName ContactName Address City PostalCode Country
1
 		 Alfreds Futterkiste Maria Anders Obere Str. 57 Berlin 12209 Germany
2 Ana Trujillo Emparedados y helados Ana Trujillo Avda. de la Constitución 2222 México D.F. 05021 Mexico
3 Antonio Moreno Taquería Antonio Moreno Mataderos 2312 México D.F. 05023 Mexico
4
 		 Around the Horn Thomas Hardy 120 Hanover Sq. London WA1 1DP UK
5 Berglunds snabbköp Christina Berglund Berguvsvägen 8 Luleå S-958 22 Sweden

Yuqoridagi namunani DISTINCT-siz, SELECT orqali tanlab olamiz:

Quyidagi SQL buyruq "Xaridorlar" jadvalidagi "Country" ustunidan barcha qiymatlar(o'xshash qiymlarni ham)ni tanlab oladi:

SELECT Country FROM Customers;

Endi ushbu namunani, SELECT DISTINCT bilan ko'rsak:

SELECT DISTINCT Country FROM Customers;

Quyidagi SQL buyruqda, xaridorlarning bir-biriga o'xshash bo'lmagan holda davlatlar sonini chiqarib beradi:

SELECT COUNT(DISTINCT Country) FROM Customers;

 

Mavzular ro'yhati

MySQL ga kirish SQL haqida va buyruqlar SQL: create buyrug'i SQL: alter so'rovi TRUNCATE, DROP va RENAME so'rovlari INSERT so'rovi SELECT DISTINCT buyrug'i Java SE, Oracle Database 11g Express Edition, Oracle SQL Developer SELECT, WHERE, ORDER BY, DESC, LIKE Select, Where... II Select, where III Select, where... IV Select, where ... V Select, where... VI Select, where... VII Select, where... VIII Select, where 9-dars Select, where 10-qism Select, where 11-qism Select,where 12-qism Select,where 13-qism Select,where 14-qism Select,where 15-qism Select,where 16-qism Select,where 17-qism Select,where 18-qism Select,where 19-qism Select,where 20-qism Bir tipdan boshqasiga o`girish Bir tipdan boshqasiga o`girish (Qoidalar) Bir tipdan boshqasiga avtomatik o`girishga misollar Bir tipdan boshqasiga o`girishda ogohlantirishlar Guruhlash Guruhlash (Queryning bajarilish tartibi) Guruhlashda View lardan foydalanish Guruhlashda HAVING ning qo`llanilishi Quyi so'rovlar Quyi so'rovlar II Exists Join ko'rsatmasi NOT IN, NOT EXISTS Natural, inner join Union,intersect,minus Vaqtni insert qilish Select orqali insert qilish ROLLBACK, COMMIT va AUTOCOMMIT INSERT ALL INSERT ALL va INSERT FIRST DELETE va TRUNCATE Update SUBQUERY yordamida UPDATE, NULL ga UPDATE qilish MERGE