Only OLAP functions with the same PARTITON/ORDER BY can be calculated in a single step and your ROW_NUMBERs got the same ORDER BY (which is just a dummy order, btw), but different PARTTION.
It's similar to multiple COUNT(DISTINCT), which are easy to write, but really hard to calculate.
Only OLAP functions with the same PARTITON/ORDER BY can be calculated in a single step and your ROW_NUMBERs got the same ORDER BY (which is just a dummy order, btw), but different PARTTION.
It's similar to multiple COUNT(DISTINCT), which are easy to write, but really hard to calculate.
Dieter