On Fri, Mar 01, 2019 at 11:51:24AM +0100, Ila B. wrote:
> Hello,
>
> I’m working on a health database and I’m trying to extract the most popular prescription codes from a custom table I
structuredlike this:
>
> Year - Code - Count(code)
>
> I want to extract the 3 codes with maximum count for each year. I know I should be using rank() but I don’t really
understandhow this works.
> I am using pgAdmin4 version 3.5 with PostgreSQL 10.6 on Windows 10 Pro and no permission to update.
Consider reading
https://www.depesz.com/2012/10/05/getting-top-n-rows-per-group/
Best regards,
depesz