Missing 'Median' Aggregate Function in Django?

Question

The Development version of Django has aggregate functions like Avg, Count, Max, Min, StdDev, Sum, and Variance (link text). Is there a reason Median is missing from the list

Answer 1

Well, the reason is probably that you need to track all the numbers to calculate median. Avg, Count, Max, Min, StDev, Sum, and Variance can all be calculated with constant storage needs. That is, once you "record" a number you'll never need it again.

FWIW, the variables you need to track are: min, max, count, = avg, = avg of the square of the values.