SQLSERVER行转列的2种实现方式

IF(OBJECT_ID('tbl_bigcode_pivot') IS NOT NULL)
BEGIN
DROP TABLE dbo.tbl_bigcode_pivot
END
GO

CREATE TABLE tbl_bigcode_pivot
(
	[像素编号] INT,
	[波段] INT,
	[像素值] FLOAT
)

INSERT INTO tbl_bigcode_pivot
SELECT 400 [像素编号], 1 [波段],0.021347 [像素值]
UNION ALL 
SELECT 400 [像素编号], 2 [波段],0.021195 [像素值]
UNION ALL 
SELECT 400 [像素编号], 3 [波段],0.020949 [像素值]
UNION ALL 
SELECT 401 [像素编号], 1 [波段],0.021366 [像素值]
UNION ALL 
SELECT 401 [像素编号], 3 [波段],0.020968 [像素值]
UNION ALL 
SELECT 402 [像素编号], 1 [波段],0.021378 [像素值]
UNION ALL 
SELECT 402 [像素编号], 2 [波段],0.021226 [像素值]
UNION ALL 
SELECT 402 [像素编号], 3 [波段],0.02098 [像素值]


SELECT * FROM tbl_bigcode_pivot

--CASE方式实现
SELECT [像素编号],
	   MAX(CASE [波段] WHEN 1 THEN [像素值] ELSE 0 END) [1],
	   MAX(CASE [波段] WHEN 2 THEN [像素值] ELSE 0 END) [2],
	   MAX(CASE [波段] WHEN 3 THEN [像素值] ELSE 0 END) [3]
FROM tbl_bigcode_pivot GROUP BY [像素编号]

--PIVOT函数实现
SELECT [像素编号],CONVERT(DECIMAL(18,6),ISNULL([1],0)) AS [1],CONVERT(DECIMAL(18,6),ISNULL([2],0)) AS [2],CONVERT(DECIMAL(18,6),ISNULL([3],0)) AS [3] FROM dbo.tbl_bigcode_pivot PIVOT(MAX([像素值]) FOR [波段] IN([1],[2],[3])) dtpiv