An aggregate table stores summarized results rather than individual observations. Its grain tells you what each row represents: one row per fruit type, for example, instead of one row per fruit eaten. section 3.5.1
From fruit observations to a roll-up
Start with individual fruits and their taste scores. Group rows by fruit type, keep the maximum taste score for each group, then sort by descending taste and ascending name. The result is an aggregate, or roll-up, table. section 3.5.1
