CUME_DIST函數以某列作為基準，計算其它行相對于基準行數據的比例、差距比例，比較容易理解

先看下測試數據

DECLARE @TestData TABLE(     ID INT IDENTITY(1,1),     Department VARCHAR(20),     LastName VARCHAR(20),     Rate FLOAT ) INSERT INTO @TestData(Department,LastName,Rate) SELECT 'Document Control','Arifin',17.7885 UNION ALL SELECT 'Document Control','Norred',16.8269 UNION ALL SELECT 'Document Control','Kharatishvili',16.8269 UNION ALL SELECT 'Information Services','Chai',10.25 UNION ALL SELECT 'Information Services','Berge',10.25 UNION ALL SELECT 'Information Services','Trenary',50.4808 UNION ALL SELECT 'Information Services','Conroy',39.6635 UNION ALL SELECT 'Information Services','Ajenstat',38.4615 UNION ALL SELECT 'Information Services','Wilson',38.4615 UNION ALL SELECT 'Information Services','Connelly',32.4519 UNION ALL SELECT 'Information Services','Meyyappan',32.4519

SELECT * FROM @TestData

第一個例子，代碼比較簡單，結果集里出來的一列Cume_Dist

第二個例子，與例1不同的是添加了分組，CUME_DIST被應用到每個組內，即每個組內有一個自己的基準，組內其它成員參照此基準進行運算

還有一個類似的函數，PERCENT_RANK，先猜猜這個函數做什么用？