sql - 引用别名而不是重复计算

Question

我有一个查询：

SELECT   [outer].*,
         (total_pain_patients / NULLIF ((SELECT Sum(total_pain_patients)
             FROM   [topplansperprovider]
             WHERE  [outer].[INDEX_IMSID] = [INDEX_IMSID]
             AND plan_rank BETWEEN 1 AND 10), 0)) * 100 AS PercentOf,
         pm.*,
         percentof * pm.score
FROM     [topplansperprovider] AS [outer]
left JOIN [payer Mapping] pm
on lower([outer].Plan_Name_OR_Payment_Type)=lower(pm.[ims payer name])
WHERE    INDEX_IMSID = '1753841'
ORDER BY 6 ASC

我的问题是选择这个：

percentof * pm.score

由于percentof是派生列的别名，我不知道如何在其他列中使用它。

1. 我该如何选择percentof * pm.score？
2. 如果这太难了，我怎样才能将percentof作为永久列添​​加到我的表中？

Answer 1

您不能使用这样的别名，您必须将查询包装在另一个选择中：

select x.*, x.percentof*x.pm.score newvalue
from
(
    SELECT   [outer].*,
             (total_pain_patients / NULLIF ((SELECT Sum(total_pain_patients)
                                             FROM   [topplansperprovider]
                                             WHERE  [outer].[INDEX_IMSID] = [INDEX_IMSID]
                                                    AND plan_rank BETWEEN 1 AND 10), 0)) * 100 PercentOf,
             pm.*
    FROM     [topplansperprovider] AS [outer]
    left JOIN [payer Mapping] pm
        on lower([outer].Plan_Name_OR_Payment_Type)=lower(pm.[ims payer name])
) x
WHERE    x.INDEX_IMSID = '1753841'
ORDER BY 6 ASC

您正在计算的列别名percentof不可用于另一列，除非它在子查询中使用。

Answer 2

创建视图：

CREATE VIEW dbo.whatever
AS 
    SELECT 
      t.*, -- NAME THESE COLUMNS!!!
      PercentOf = (t.total_pain_patients / NULLIF ((SELECT Sum(t2.total_pain_patients)
         FROM   dbo.[topplansperprovider] AS t2
         WHERE  t2.[INDEX_IMSID] = t.[INDEX_IMSID]
         AND t2.plan_rank BETWEEN 1 AND 10), 0)) * 100,
      pm.* -- NAME THESE COLUMNS!!!
  FROM dbo.[topplansperprovider] AS t
  LEFT OUTER JOIN dbo.[payer Mapping] AS pm
  ON LOWER(t.Plan_Name_OR_Payment_Type) = LOWER(pm.[ims payer name])
  WHERE t.INDEX_IMSID = '1753841';
GO

现在您的查询可以是：

SELECT *, [something] = PercentOf * score -- NAME THIS ALIAS!
  FROM dbo.whatever
  ORDER BY 6 ASC; -- NAME THIS COLUMN!!!

但是，请停止使用惰性SELECT *语法，尤其是在视图中：

• 要踢的坏习惯：使用 SELECT * / 省略列列表

请停止使用ORDER BY [ordinal]：

• 要踢的坏习惯 : ORDER BY ordinal

这些都是最终会导致你痛苦的坏习惯。

Answer 3

虽然不是最佳答案，但您可以创建一个视图以在视图中具有“永久”列。