Item 47: Produce Combinations of Rows between Two Tables and Flag Rows in the Second That Indirectly Relate to the FirstThings to RememberItem 48: Understand How to Rank Rows by Equal QuantilesThings to RememberItem 49: Know How to Pair Rows in a Table with All Other RowsThings to RememberItem 50: Understand How to List Categories and the Count of First, Second, or Third PreferencesThings to Remember