What is a Rollup Table?
Simply described, a rollup table is a physical table that pre-aggregates another table. This idea originally had its origins in accounting, where specific general ledger categories were “rolled up” into broader categories, which were in turn “rolled up” into broader categories. Ultimately, all categories “rolled up” into two categories: Income and Expense. At each level of rollup, people could see the amounts summarized at that particular level. Sometimes people wanted to see transactions at the detail level; other times they wanted see subtotals at the project or category level; and other times they wanted to see totals at a summary level. Any database table can be similarly rolled up. While an accounting system summarizes dollar amounts, databases can summarize any information contained in the database. An orders database can summarize order amounts, order quantities, discounts, taxes, credit limits, or any other information stored in the table. This information can be pre-aggregated
