Question

Here I have some articles:

id  text  group_id source_id
1   t1    1        1
2   t2    1        1
3   t3    2        2
4   t4    3        4

So I want to have records in result ordered by created_at column (it exists, but I didn’t show it in table) and having distinct group id, such as that:

id  text  group_id source_id
1   t1    1        1
3   t3    2        2
4   t4    3        4

Also, I should be able to filter result with source_id.

I’m stuck with this question for two days and don’t even know how to start solve problem.

Answer 1

Assuming you want the minimum values of the non-duplicated columns, try:

select   min(id) as id, 
         min(text) as text, 
         group_id, 
         source_id, 
         min(created_at) as created_at
from     articles
where    source_id = @your_parameter_value
group by group_id,
         source_id
order by 5