7 laboratoriya ishi

Having max (Hour)>= 34;
Having
So’rov: SELECT price, COUNT(*) AS count
FROM products
GROUP BY price
HAVING price > 1000;
Natija:

11.5 – rasm. Group by va Having kalit so’zlarining qo’llanilishi


5. COUNT() – Ustundagi qatorlar sonini sanaydi.
So’rov: Select id as ‘2 tadan kop maxsulot ishlab chiqaradigan korpuslar id lari’ , count(maxsulot_nomi) as ‘maxsulotlar soni’ from maxsulot group by korpus_id having count(maxsulot_nomi)>=2;
Natija:

1. 
   Rand() - tasodifiy son.
   

So’rov: Select id, f_i_sh, rand(id) from xodimlar;
Natija:
7. ROUND() - Butun sonni yaxlitlash funktsiyasi.
So`rov: Select id, maxsulot_nomi, round(korpus_id/qurilma_id, 3) from maxsulot;
Natija:

9. SQRT() - Sonning kvadrat ildizini topish.
So`rov:Select id, sqrt(id) from bemorlar;

Natija:
INDEX
So`rov: show tables from foydali_qazilma_boyitish_zavodi;
Natija:

13.1 – rasm. Products jadvali .
So`rov: CREATE INDEX idx_products_price ON products (price);
Natija:

13.2 – rasm. Ishlatilishi jadvali uchun indeks yaratish
Yaratgan indeksimizni ko’ramiz:
So`rov: SELECT *
FROM pg_indexes
WHERE tablename = 'products';
Natija:

13.3 – rasm. Products jadvali uchun yaratilgan indekslar ro`yxati
So’rov: DROP INDEX idx_products_price;
Natija:

13.4- rasm. Products jadvali uchun yaratilgan indexlarni o’chirish.