日常有时候导出数据需求时,数据列会遇到带有分隔符的ID,但又需要匹配维表(如下图所示)将ID变成名称。
这种情况可以采用“分隔-匹配-合并”的方法
具体代码为:
-- 准备工作1:创建事实表数据 CREATE TABLE #StudentSubject ( StuID INT IDENTITY(1,1) NOT NULL, StuSubject VARCHAR(500) NOT NULL ) INSERT INTO #StudentSubject(StuSubject) VALUES (‘1‘) INSERT INTO #StudentSubject(StuSubject) VALUES (‘2‘) INSERT INTO #StudentSubject(StuSubject) VALUES (‘2,3‘) INSERT INTO #StudentSubject(StuSubject) VALUES (‘2,3,4‘) INSERT INTO #StudentSubject(StuSubject) VALUES (‘1,2,3,4‘) INSERT INTO #StudentSubject(StuSubject) VALUES (‘4‘) -- 准备工作2:创建维表数据 CREATE TABLE #D_Subject ( SubjectID INT IDENTITY(1,1) NOT NULL, SubjectName VARCHAR(500) NOT NULL ) INSERT INTO #D_Subject(SubjectName) VALUES (‘语文‘) INSERT INTO #D_Subject(SubjectName) VALUES (‘数学‘) INSERT INTO #D_Subject(SubjectName) VALUES (‘英语‘) INSERT INTO #D_Subject(SubjectName) VALUES (‘体育‘) SELECT * FROM #StudentSubject SELECT * FROM #D_Subject ; -- 1分离:将逗号分隔的StuSubject分离匹配StudentSubject获取标签 WITH CetSubject AS ( SELECT StuID, CAST(LEFT(StuSubject, CHARINDEX(‘,‘, StuSubject + ‘,‘) - 1) AS NVARCHAR(100)) SubjectID, CAST(STUFF(StuSubject + ‘,‘, 1, CHARINDEX(‘,‘, StuSubject + ‘,‘), ‘‘) AS NVARCHAR(100)) Split FROM #StudentSubject UNION ALL SELECT StuID, CAST(LEFT(Split, CHARINDEX(‘,‘, Split) - 1) AS NVARCHAR(100)) SIds, CAST(STUFF(Split, 1, CHARINDEX(‘,‘, Split), ‘‘) AS NVARCHAR(100)) Split FROM CetSubject WHERE split > ‘‘ ) -- 2匹配 将分离后的数据逐行与维表匹配 SELECT CS.StuID, DS.SubjectName INTO #CetSubjectName FROM CetSubject CS LEFT JOIN #D_Subject DS ON DS.SubjectID = CS.SubjectID WHERE CS.SubjectID <> ‘‘ OPTION (MAXRECURSION 0); -- 3合并 将与维表匹配的结果用逗号分隔合并还原 SELECT StuID, STUFF((SELECT ‘,‘ + T.SubjectName FROM #CetSubjectName T WHERE T.StuID = T2.StuID FOR XML PATH(‘‘)),1,1,‘‘) SubjectName FROM #CetSubjectName t2 GROUP BY StuID DROP TABLE #D_Subject DROP TABLE #StudentSubject DROP TABLE #CetSubjectName
原文地址:https://www.cnblogs.com/kylan/p/10541653.html
时间: 2024-11-04 16:05:09