Instruction
Okay, let's start with something easy.
Exercise
Show the average distance driven for the following grouping combinations:
year,month, anddayyearandmonthyear- None (general average)
In the query result, show the following columns: year, month, day, and avg_distance.
Stuck? Here's a hint!
A natural candidate for this query is:
GROUP BY ROLLUP(year, month, day)



