sql面试题：行转列

CREATE TABLE ProgrectDetail
(
    ProgrectName         NVARCHAR(20), --工程名称
    OverseaSupply        INT,          --海外供应商供给数量
    NativeSupply         INT,          --国内供应商供给数量
    SouthSupply          INT,          --南方供应商供给数量
    NorthSupply          INT           --北方供应商供给数量
)

INSERT INTO ProgrectDetail
SELECT 'A', 100, 200, 50, 50
UNION ALL
SELECT 'B', 200, 300, 150, 150
UNION ALL
SELECT 'C', 159, 400, 20, 320
UNION ALL
SELECT 'D', 250, 30, 15, 15

 行转列后：

SELECT P.ProgrectName,P.Supplier,P.SupplyNum
FROM 
(
    SELECT ProgrectName, OverseaSupply, NativeSupply,
           SouthSupply, NorthSupply
     FROM ProgrectDetail
)T
UNPIVOT 
(
    SupplyNum FOR Supplier IN
    (OverseaSupply, NativeSupply, SouthSupply, NorthSupply )
) P