OLAP queries
- Aggregating a measure over one or more dimensions
- Examples
- Find the total sales
- Find total sales for each city
- find total sales for each state
- find the top five products ranked by total sales
- Dimensionality reduction: aggregating on a dimension
- Summarizing at different levels of dimension hierarchy
- Roll-up: from lower to higher dimension: sales per city to sales per state
- Drill-down: inverse of roll-up. Can be done on different dimensions
- Pivoting: cross-tabulating a measure along multiple dimensions
- Example: pivoting sales by year and state
- Queries across time dimension
- Find total sales by month
- Find the total sales by month for each city
- Find the percentage change in total monthly sales for each product
- Find the trailing n day moving average of sales
- Slicing: equality selection on one or more dimension
- Dicing: range selection on one or more dimension
- total sales by year, state and product category for year
between 1995-1997 and product category in (‘HW’, ‘SG’, ‘AP’)