How to unpivot columns using CROSS APPLY in SQL Server 2012

问题

I want to use CROSS APPLY to UNPIVOT multiple columns.

The columns CGL, CPL, EO should become Coverage Type, the values for CGL, CPL, EO should go in column Premium, and values for CGLTria,CPLTria,EOTria should go in column Tria Premium

declare @TestDate table  ( 
                            QuoteGUID varchar(8000), 
                            CGL money, 
                            CGLTria money, 
                            CPL money,
                            CPLTria money,
                            EO money,
                            EOTria money
                            )

INSERT INTO @TestDate (QuoteGUID, CGL, CGLTria, CPL, CPLTria, EO, EOTria)
VALUES ('2D62B895-92B7-4A76-86AF-00138C5C8540', 2000, 160, 674, 54, 341, 0),
       ('BE7F9483-174F-4238-8931-00D09F99F398', 0, 0, 3238, 259, 0, 0),
       ('BECFB9D8-D668-4C06-9971-0108A15E1EC2', 0, 0, 0, 0, 0, 0)

SELECT * FROM @TestDate

Output:

The result should be like that :

回答1:

One quick and easy way is with VALUES

Example

select A.QuoteGUID
      ,B.*
 From  @TestDate A
 Cross Apply ( values ('CGL',CGL,CGLTria)
                     ,('CPL',CPL,CPLTria)
                     ,('EO',EO,EOTria)
             ) B (CoverageType,Premium,TiraPremium)

Returns

来源：https://stackoverflow.com/questions/48654306/how-to-unpivot-columns-using-cross-apply-in-sql-server-2012