Re: How to select unique records in PostgreSQL

Honestly, you do it *in PostgreSQL* the same way you do it in all the other
SQL RDBMSs.

On 11/24/22 06:01, Rama Krishnan wrote:
>
> 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
>
>
> Regards
>
> A.Rama Krishnan

--
Angular momentum makes the world go 'round.