Simplify reporting queries with four new SQL 2005 Transact-SQL functions

摘要

As Figure A shows, the ROW_NUMBER function adds a column to the resultset where the number is incremented for each row displayed. The ROW_NUMBER function, like the other ranking functions we'll discuss, doesn't rely on the physical order of the resultset. Rather, you need to supply the OVER clause to tell it how to order rows when it calculates the rank. In this case, the OVER clause specifies an ORDER BY clause; you can also include a partitioning clause as we'll show you later.