T-SQL ENHANCEMENTS 10297 BLONP 8 10360 BLONP 8

T-SQL ENHANCEMENTS 10297 BLONP 8 10360 BLONP 8 … more rows Note that multiple rows have the same rank if their customerid is the same. There are holes, however, in the rankcolumn value to reflect the ties. Using the DENSE_RANK()function works the same way as RANK()but gets rid of the holes in the numbering. NTILE(n) divides the resultset into n approximately even pieces and assigns each piece the same number. NTILE(100) would be the well-known (to students) percentile. The following query shows the difference between ROW_NUMBER(), RANK(), DENSE_RANK(), and TILE(n). SELECT orderid, customerid, ROW_NUMBER() OVER(ORDER BY customerid) AS num, RANK() OVER(ORDER BY customerid) AS [rank], DENSE_RANK() OVER(ORDER BY customerid) AS [denserank], NTILE(5) OVER(ORDER BY customerid) AS ntile5 FROM orders WHERE orderid < 10400 AND customerid <= BN produces orderid customerid num rank denserank ntile5 - - 10308 ANATR 1 1 1 1 10365 ANTON 2 2 2 1 10355 AROUT 3 3 3 2 10383 AROUT 4 3 3 2 10278 BERGS 5 5 4 3 10280 BERGS 6 5 4 3 10384 BERGS 7 5 4 4 10265 BLONP 8 8 5 4 10297 BLONP 9 8 5 5 10360 BLONP 10 8 5 5 The ranking functions have additional functionality when combined with windowing functions. Windowing functions divide a resultset into partitions, based on the value of a PARTITION BY clause inside the OVER clause. The ranking functions are applied separately to each partition. Here s an example. SELECT *, RANK() OVER(PARTITION BY COUNTRY ORDER BY age) AS [rank] FROM ( Note: If you are looking for good and high quality web space to host and run your application check Lunarwebhost Java Web Hosting services

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