There’s a widespread misconception that SQL Server’s columnstore indexes are like an index on every column.
I debunk that myth in the first 30 minutes of my Fundamentals of Columnstore class, where I explain that a better way to think of them is that your table is broken up into groups of rows (1M rows or less per group), and in each group, there’s an index on every column.
So essentially, every column has a whole bunch of indexes on it.
But there’s no order whatsoever as to which rows end up in which index.
This isn’t a problem for