sqlserver字符串多行合并为一行

Posted 2020-10-19 大漠孤烟直

 1 --创建测试表
 2 CREATE TABLE [dbo].[TestRows2Columns](
 3     [Id] [int] IDENTITY(1,1) NOT NULL,
 4     [UserName] [nvarchar](50) NULL,
 5     [Subject] [nvarchar](50) NULL,
 6     [Source] [numeric](18,0) NULL
 7 )
 8 GO
 9 
10 --插入测试数据
11 INSERT INTO [TestRows2Columns] ([UserName],[Subject],[Source]) 
12     SELECT N‘张三‘,N‘语文‘,60  UNION ALL
13     SELECT N‘李四‘,N‘数学‘,70  UNION ALL
14     SELECT N‘王五‘,N‘英语‘,80  UNION ALL
15     SELECT N‘王五‘,N‘数学‘,75  UNION ALL
16     SELECT N‘王五‘,N‘语文‘,57  UNION ALL
17     SELECT N‘李四‘,N‘语文‘,80  UNION ALL
18     SELECT N‘张三‘,N‘英语‘,100
19 GO
20 
21 SELECT * FROM [TestRows2Columns]
22 
23 
24 
25 
26 --1 通过 select 累加
27 DECLARE @sql_col VARCHAR(8000)
28 SELECT @sql_col = ISNULL(@sql_col + ‘,‘,‘‘) + QUOTENAME([Subject]) FROM TestRows2Columns 
29 GROUP BY [Subject]
30 
31 SELECT @sql_col
32 
33 
34 
35 
36 --2 通过 FOR xml path(‘‘) 合并字符串记录
37 SELECT 
38     STUFF(
39         (SELECT ‘#‘ + Subject
40          FROM TestRows2Columns
41          WHERE UserName = ‘王五‘
42          FOR xml path(‘‘)
43         ),1,1,‘‘
44         )
45   
46  
47 --3 分组合并字符串记录
48 SELECT
49     UserName,
50     Subject = (
51                STUFF(
52                     (SELECT ‘#‘ + Subject
53                      FROM TestRows2Columns
54                      WHERE UserName = A.UserName
55                      FOR xml path(‘‘)
56                     ),1,1,‘‘
57                     )
58                  )
59 FROM TestRows2Columns A
60 GROUP by UserName