Counting rows with reduceCount()

- [Instructor] Reduced count counts whatever precedes it,…so it might count the number of rows…or the number of groups.…The type chart, shown here, may well be based…on a reduced count, because it's giving us…the number of payments grouped by payment method,…and you can see tab is eight, cash and visa are both two.…When we create a group or group all…and have a look inside, we see that Crossfilter…has automatically run a reduced count for us.…So, I'm going to show you a few statements…that are equivalent to each other.…

First one we've already seen:…facts dot group all dot value,…and you may be able to remember…that that gives us a row count of 12, and that is equivalent…to facts dot group all dot…reduce count dot value,…because group all runs reduce count by default.…So, if we were to have a look at that in Firefox,…we see they're both output 12.…Now, for some other equivalent statements, we can try…type dimension dot group all.…

Now, these two statements are also equivalent to each other,…but, although they both output 12, they're not equivalent…