2. 6-union, intersect va minus standart so’zlaridan foydalanish ishdan maqsad

So`rov: select * from mahsulot INTERSECT select * from guruhi

So`rov: select * from mahsulot MINUS select * from guruhi

SQL UNION operatori

Operator ikki yoki undan ortiq bayonotlarning UNIONnatijalar to'plamini birlashtirish uchun ishlatiladi .SELECT

• 
  Har bir SELECTbayonotda UNIONbir xil sonli ustunlar bo'lishi kerak
  
• 
  Ustunlar ham o'xshash ma'lumotlar turlariga ega bo'lishi kerak
  
• 
  Har bir SELECTbayonotdagi ustunlar ham bir xil tartibda bo'lishi kerak
  

UNION sintaksisi

SELECT column_name(s) FROM table1

UNION
SELECT column_name(s) FROM table2;

UNION ALL sintaksisi

Operator UNIONsukut bo'yicha faqat alohida qiymatlarni tanlaydi. Ikki nusxadagi qiymatlarga ruxsat berish uchun foydalaning UNION ALL:

SELECT column_name(s) FROM table1

UNION ALL
SELECT column_name(s) FROM table2;