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From: Ila B. <ilaria.battiston@gmail.com>
To: pgsql-sql@lists.postgresql.org
Subject: Top 3 values for each group in PGSQL
Date: Fri, 1 Mar 2019 11:51:24 +0100
Message-ID: <67FB61BF-CF8F-440E-B4C5-B6F72D61A9C7@gmail.com> (raw)

Hello,

I’m working on a health database and I’m trying to extract the most popular prescription codes from a custom table I structured like 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 understand how this works.
I am using pgAdmin4 version 3.5 with PostgreSQL 10.6 on Windows 10 Pro and no permission to update.

Thank you in advance,
Ilaria

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