Hugo Kornelis has gotten into the video game:
Below, you find my first video blog. I talk about the OVER clause, and I hope to convince you why you should always explicitly specify the ROWS or RANGE clause – even though that takes a bit more typing.
Understanding what the default frames look like for your queries is important. And it’s important to note that the default frame is different based on whether you use SUM(x) OVER() or SUM(x) OVER(ORDER BY X). It also doesn’t matter for ranking window functions (ROW_NUMBER(), RANK(), DENSE_RANK(), NTILE()) because you’re not allowed to specify a window frame.