sql中的行转列和列转行的问题

CREATE TABLE #T
(
  MON1 INT,
  MON2 INT,
  MON3 INT
)
GO
INSERT INTO #T VALUES(1,2,3)
GO
SELECT * FROM #T

--行转列；（union all）

SELECT MON1 FROM #T
UNION ALL
SELECT MON2 FROM #T
UNION ALL
SELECT MON3 FROM #T
GO

--最后的优化
SELECT * FROM (
SELECT MON1 FROM #T
UNION ALL
SELECT MON2 FROM #T
UNION ALL
SELECT MON3 FROM #T
) T

 --创建表
  GO
  CREATE TABLE #T1(
   NAME NVARCHAR(100),
   CHINESE NVARCHAR(100),
   MATH NVARCHAR(100),
   ENGLISH NVARCHAR(100)
  )
  --插入模拟数据
  SELECT * FROM #T1
  GO
  INSERT INTO #T1 VALUES(‘张三‘,80,90,90)
  INSERT INTO #T1 VALUES(‘李四‘,47,78,null)
  INSERT INTO #T1 VALUES(‘王五‘,null,90,null)
  GO
  SELECT * FROM #T1
  
  --具体代码实现
  GO
  SELECT * FROM (
  SELECT NAME AS ‘姓名‘,‘语文‘ AS ‘科目‘,CHINESE AS ‘成绩‘ FROM #T1
  UNION ALL
  SELECT NAME AS ‘姓名‘,‘数学‘ AS ‘科目‘,MATH AS ‘成绩‘ FROM #T1
  UNION ALL
  SELECT NAME  AS ‘姓名‘,‘英语‘ AS ‘科目‘,ENGLISH AS ‘成绩‘ FROM #T1
  ) T
  order by T.姓名  

  --方法二；这个方法 会自动去除值为 NULL 的值
  SELECT NAME,OBJ,GRADE
  FROM #T1
  UNPIVOT(GRADE FOR OBJ IN (CHINESE,MATH,ENGLISH)) AS UP

CREATE TABLE #T0
(
  MON1 INT
)
INSERT INTO #T0 VALUES(1)
INSERT INTO #T0 VALUES(2)
INSERT INTO #T0 VALUES(3)

SELECT * FROM #T0
--方法一 仅仅限制于 数据不重复的情况下
SELECT
(SELECT MON1 FROM #T0 WHERE MON1=1) ‘1‘,
(SELECT MON1 FROM #T0 WHERE MON1=2) ‘2‘,
(SELECT MON1 FROM #T0 WHERE MON1=3) ‘3‘