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Wow I love me a window function! Favorite/weirdest thing I learned to do most recently with window functions is using/abusing min() and max(). If there is no
by hospadar 6y ago
Wow I love me a window function!
Favorite/weirdest thing I learned to do most recently with window functions is using/abusing min() and max(). If there is no value in a column in a particular window, min and max will give NULL.
We use this to do really interesting stuff (entirely in sql!) like "partition usage into sessions where a session is defined as a bunch of activity by a user where they did an action at least once every 30 minutes"
- marcosdumay 6y agoSQL could really use some standard aggregation function that returns null for no rows, the value of a single row and error if there is more than one row. That kind of query happens all the time, and min/max behavior isn't the safest one.