Re: Selecting table row with latest date

On 8/19/21 10:17 AM, Rich Shepard wrote:
> On Thu, 19 Aug 2021, Adrian Klaver wrote:
>
>> So take David Johnston's query:
>> Select distinct on (person_nbr) ….. order by person_nbr, contact_date
>> desc;
>
> Adrian,
>
> contact_date --------------
>  2021-08-17
>  2019-05-14
>  2019-05-15
>  2021-08-17
>  2018-04-05
>  2021-08-17
>  2018-04-05
>  2021-07-23
>  2019-04-01
>  2019-05-10
>  2019-03-15
>  2021-08-17
>  2019-04-16
>  2019-05-15
>  2021-08-17
>  2019-05-29
>  2021-08-17
>  2019-05-29
>  2021-07-23
>  2021-08-12
> ...

So is the above the result of the query above or the query I posted below?

Why is there no other information to provide context?

Is it doing what you want?

>
>> and add the next_contact filter:
>>
>> Select distinct on (person_nbr) * from contacts where next_contact <=
>> current_date order by person_nbr, contact_date desc;

>
> Select distinct on (p.person_nbr) * from c.contacts
> from people as p, contacts as c
> where cnext_contact <= current_date and
> p.person_nbr = c.person_nbr
> order by p.person_nbr, c.contact_date desc;
>
> $ psql -d bustrac -f test_query.sql
> psql:test_query.sql:5: ERROR:  syntax error at or near "from"
> LINE 2: from people as p, contacts as c
>         ^
>
> I still am missing quite a bit.
>
> Rich
>
>
>

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com