SQL 多列转换为一行【转】

--创建测试表
IF OBJECT_ID('test') IS NOT NULL
    DROP TABLE test
CREATE TABLE dbo.test(
    id int IDENTITY(1,1) NOT NULL,
    name varchar(50) NULL,
    subject varchar(50) NULL,
    source decimal(18,2) NULL
)
GO

--插入测试数据
INSERT INTO test (name,subject,source) 
    SELECT '张三','语文',60  UNION ALL
    SELECT '张三','英语',90  UNION ALL
    SELECT '李四','语文',70  UNION ALL
    SELECT '李四','数学',80  UNION ALL
    SELECT '王五','数学',75  UNION ALL
    SELECT '王五','英语',80
GO

SELECT * FROM test

--1 通过 select 累加
DECLARE @sql_col VARCHAR(8000)
SELECT @sql_col = ISNULL(@sql_col + ',','') + QUOTENAME(Subject) FROM test 
GROUP BY Subject

SELECT @sql_col

--2 通过 FOR xml path('') 合并字符串记录
SELECT 
    STUFF(
        (SELECT '#' + Subject
         FROM test
         WHERE name = '王五'
         FOR xml path('')
        ),1,1,''
        )
  
--3 分组合并字符串记录
SELECT
    name,
    Subject = (
               STUFF(
                    (SELECT '#' + Subject
                     FROM test
                     WHERE name = A.name
                     FOR xml path('')
                    ),1,1,''
                    )
                 )
FROM test A
GROUP by name

转自：https://www.cnblogs.com/xiaozhi1236/p/6344134.html?utm_source=itdadao&utm_medium=referral