Can someone please explain what the partition by keyword does and give a simple example of it in action, as well as why one would want to use it? I have a SQL query written by someone else and I’m trying to figure out what it does.
An example of partition by:
SELECT empno, deptno, COUNT(*)
OVER (PARTITION BY deptno) DEPT_COUNT
FROM emp
The examples I’ve seen online seem a bit too in-depth.
