SQL Server 2008 R2——ROW_NUMBER() 去掉不同行中相同列的重复内容
USE tempdb GO -------------------------------------------------------------------------- IF OBJECT_ID('Student','U') IS NOT NULL DROP TABLE Student GO CREATE TABLE Student ( StuID NVARCHAR(8) PRIMARY KEY, Name NVARCHAR(5) ) GO INSERT INTO Student(StuID,Name) VALUES('20080001','Lily') INSERT INTO Student(StuID,Name) VALUES('20080002','Lucy') INSERT INTO Student(StuID,Name) VALUES('20080003','Jack') GO -------------------------------------------------------------------------- IF OBJECT_ID('SltCourse','U') IS NOT NULL DROP TABLE SltCourse GO CREATE TABLE SltCourse --SelectiveCourse ( ID INT PRIMARY KEY IDENTITY(1,1), StuID NVARCHAR(8), CourseName NVARCHAR(10), Score INT ) GO INSERT INTO SltCourse(StuID,CourseName,Score) VALUES('20080003','电脑维修',90) INSERT INTO SltCourse(StuID,CourseName,Score) VALUES('20080003','剪纸',80) INSERT INTO SltCourse(StuID,CourseName,Score) VALUES('20080003','市场策划',95) INSERT INTO SltCourse(StuID,CourseName,Score) VALUES('20080003','信息检索',100) INSERT INTO SltCourse(StuID,CourseName,Score) VALUES('20080001','插花',99) INSERT INTO SltCourse(StuID,CourseName,Score) VALUES('20080001','剪纸',96) INSERT INTO SltCourse(StuID,CourseName,Score) VALUES('20080001','刺绣',92) INSERT INTO SltCourse(StuID,CourseName,Score) VALUES('20080002','插花',98) GO -------------------------------------------------------------------------- SELECT * FROM Student GO SELECT * FROM SltCourse GO -------------------------------------------------------------------------- SELECT * FROM Student s,SltCourse sc WHERE s.stuid=sc.stuid GO -------------------------------------------------------------------------- WITH ReportCard AS( SELECT s.StuID,s.Name,sc.CourseName,sc.Score FROM Student s,SltCourse sc WHERE s.stuid=sc.stuid ) SELECT CASE WHEN RowNum=1 THEN StuID ELSE '' END AS ID, CASE WHEN RowNum=1 THEN Name ELSE '' END AS Name, CourseName, Score FROM (SELECT *,ROW_NUMBER() OVER (PARTITION BY StuID,Name ORDER BY Score) AS RowNum FROM ReportCard) TBL GO -------------------------------------------------------------------------- DROP TABLE Student GO DROP TABLE SltCourse GO
USE tempdb GO -------------------------------------------------------------------------- IF OBJECT_ID('Student','U') IS NOT NULL DROP TABLE Student GO CREATE TABLE Student ( StuID NVARCHAR(8) PRIMARY KEY, Name NVARCHAR(5), EntranceTime DATETIME ) GO INSERT INTO Student(StuID,Name,EntranceTime) VALUES('20080001','Lily','2008-08-27') INSERT INTO Student(StuID,Name,EntranceTime) VALUES('20090002','Lucy','2009-08-26') INSERT INTO Student(StuID,Name,EntranceTime) VALUES('20070003','Jack','2007-08-28') GO -------------------------------------------------------------------------- IF OBJECT_ID('SltCourse','U') IS NOT NULL DROP TABLE SltCourse GO CREATE TABLE SltCourse --SelectiveCourse ( ID INT PRIMARY KEY IDENTITY(1,1), StuID NVARCHAR(8), CourseName NVARCHAR(10), Score INT ) GO INSERT INTO SltCourse(StuID,CourseName,Score) VALUES('20070003','电脑维修',90) INSERT INTO SltCourse(StuID,CourseName,Score) VALUES('20070003','剪纸',80) INSERT INTO SltCourse(StuID,CourseName,Score) VALUES('20070003','市场策划',95) INSERT INTO SltCourse(StuID,CourseName,Score) VALUES('20070003','信息检索',100) INSERT INTO SltCourse(StuID,CourseName,Score) VALUES('20080001','插花',99) INSERT INTO SltCourse(StuID,CourseName,Score) VALUES('20080001','剪纸',96) INSERT INTO SltCourse(StuID,CourseName,Score) VALUES('20080001','刺绣',92) INSERT INTO SltCourse(StuID,CourseName,Score) VALUES('20090002','插花',98) GO -------------------------------------------------------------------------- SELECT * FROM Student GO SELECT * FROM SltCourse GO -------------------------------------------------------------------------- SELECT * FROM Student s,SltCourse sc WHERE s.stuid=sc.stuid GO -------------------------------------------------------------------------- WITH ReportCard AS( SELECT s.StuID,s.Name,s.EntranceTime,sc.CourseName,sc.Score FROM Student s,SltCourse sc WHERE s.stuid=sc.stuid ) SELECT CASE WHEN RowNum=1 THEN StuID ELSE '' END AS ID, CASE WHEN RowNum=1 THEN Name ELSE '' END AS Name, CASE WHEN RowNum=1 THEN EntranceTime ELSE '' END AS EntranceTime, CourseName, Score FROM (SELECT *,ROW_NUMBER() OVER (PARTITION BY StuID,Name,EntranceTime ORDER BY Score) AS RowNum FROM ReportCard) TBL GO -------------------------------------------------------------------------- DROP TABLE Student GO DROP TABLE SltCourse GO
WITH ReportCard AS( SELECT s.StuID,s.Name,s.EntranceTime,sc.CourseName,sc.Score FROM Student s,SltCourse sc WHERE s.stuid=sc.stuid ) SELECT CASE WHEN RowNum=1 THEN StuID ELSE '' END AS ID, CASE WHEN RowNum=1 THEN Name ELSE '' END AS Name, CASE WHEN RowNum=1 THEN EntranceTime ELSE cast(nullif('','') as datetime) END AS EntranceTime, CourseName, Score FROM (SELECT *,ROW_NUMBER() OVER (PARTITION BY StuID,Name,EntranceTime ORDER BY Score) AS RowNum FROM ReportCard) TBL GO