How to select unique records in PostgreSQL
| От | Rama Krishnan |
|---|---|
| Тема | How to select unique records in PostgreSQL |
| Дата | |
| Msg-id | CAJWX+ENP=04KZ-bHrNpwkqZL0iFuMkDdXnKK4cs0kZNJVnpM4w@mail.gmail.com обсуждение исходный текст |
| Ответы |
Re: How to select unique records in PostgreSQL
|
| Список | pgsql-general |
Hi All,
I want to get the unique wallet_id from this table even it was repeated on multiple occasions I should calculate only once as well as if the wallet_id was calculated on previous month it shouldn't be calculate on next months
create table student_id
(
student_wallet_id int,
card_id int,
created_date date
)
insert into student_id values ('w1', 'c1', '2022-04-01')
insert into student_id values ('w1', 'c2', '2022-04-03')
insert into student_id values ('w1', 'c3', '2022-04-04')
insert into student_id values ('w1', 'c4', '2022-05-01')
insert into student_id values ('w2', 'c1', '2022-05-01')
insert into student_id values ('w2', 'c2', '2022-05-04')
insert into student_id values ('w3', 'c4', '2022-05-05')
insert into student_id values ('w3', 'c6', '2022-06-03)
insert into student_id values ('w3', 'c7', '2022-06-05')
insert into student_id values ('w3', 'c8', '2022-06-07')
expected output:
-------------------
months count_wallet_id
2022-04 1
2022-05 2
2022-05 0
A.Rama Krishnan
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