UNPIVOT上的聚合和别名

Question

如何将以下查询的输出重命名（别名）默认状态（例如：QLD为Quensland）？ 另外我怎样才能将国家的预测汇总（SUM）到更高的水平（例如：国家）？

SELECT PRODUCT_BK, Month, State, Forecast 
FROM 
(SELECT * FROM Forecast_Table) t 
UNPIVOT 
(Forecast FOR State IN (SA_NT, QLD, VIC_TAS, WA, NSW_ACT)) AS fcst 

谢谢

这是一个跟进this question。

Answer 1

您可以使用case用于上述目的

SELECT PRODUCT_BK, 
     MONTH, 
     CASE [State] WHEN 'QLD' THEN 'Quensland' 
        WHEN 'SA_NT' THEN 'something else' 
        ELSE [State] 
     END AS [State], 
     Forecast 
FROM (SELECT * FROM Forecast_Table) t 
UNPIVOT (Forecast FOR State IN (SA_NT, QLD, VIC_TAS, WA, NSW_ACT)) AS fcst 

，或者作为替代方式，您可以创建#temp_table或在你的数据库@variable_table或表格，填写此表与旧&新名称，并加入最终的输出与此表。

例如：

-- create variable table to store reference between old and new alias 
DECLARE @Sometable AS TABLE 
    (
     OldName NVARCHAR(10) , 
     ShouldBeName NVARCHAR(20) 
    ) 
INSERT @Sometable 
     (OldName, ShouldBeName) 
VALUES ('SA_NT', 'Some Name 1'), 
     ('QLD', 'Some Name 2'), 
     ('VIC_TAS', 'Some Name 3'); 

--final query 
SELECT fcst.PRODUCT_BK , 
     fcst.Month , 
     COALESCE(S.ShouldBeName, fcst.[State]) AS [State] , 
     fcst.Forecast 
FROM (SELECT * FROM Forecast_Table) t 
     UNPIVOT (Forecast FOR State IN (SA_NT, QLD, VIC_TAS, WA, NSW_ACT)) AS fcst 
     LEFT JOIN @Sometable AS S ON fcst.[State] = S.OldName 

或者是，即使是这样的：

SELECT fcst.PRODUCT_BK , 
     fcst.Month , 
     COALESCE(S.ShouldBeName, fcst.[State]) AS [State] , 
     fcst.Forecast 
FROM (SELECT * FROM Forecast_Table) t 
     UNPIVOT (Forecast FOR State IN (SA_NT, QLD, VIC_TAS, WA, NSW_ACT)) AS fcst 
     LEFT JOIN (SELECT * 
        FROM (VALUES ('SA_NT', 'Some Name 1'), 
            ('QLD', 'Some Name 2'), 
            ('VIC_TAS', 'Some Name 3') 
          ) AS S (OldName, ShouldBeName) 
        ) AS S ON fcst.[State] = S.OldName