DATABASE POSTGRESQL DISTINCT DAN GROUP BY

distinct => kalo data yang double munculnya cuma satu, seperti jakarta ada dua tapi nanti cuma muncul satu.

dbkoperasi=# select distinct(alamat) as alamat from customer;

alamat

----------

Jakarta

Semarang

Kebumen

Medan

Depok

(5 rows)

group by => menampilkan jumlah grup

dbkoperasi=# select gender, count(id) as jumlah from customer group by gender;

gender | jumlah

--------+--------

L | 2

P | 4

(2 rows)

dbkoperasi=# select alamat, count(id) as jumlah from customer group by alamat; alamat | jumlah

----------+--------

Jakarta | 1

Semarang | 1

Kebumen | 2

Medan | 1

Depok | 1

(5 rows)

dbkoperasi=# select nama, count(id) as jumlah from produk group by nama;

nama | jumlah

------------------+--------

Kulkas Mini | 1

Meja Makan | 1

Teh Kotak | 1

Mie Instan | 1

Sofa Tamu | 1

Televisi 21 inch | 1

Kulkas 2 Pintu | 1

(7 rows)

dbkoperasi=# select 5 +5 as "5+5=";

5+5=

------

10

(1 row)