SQL如何在两个不同的列上产生两个具有两个不同条件的结果

我有一个SQL查询

SELECT N2 as DOORS, N2 as WINDOWS
   FROM DATABASE.dbo.DISTINTAB
        WHERE numero=45
        AND CODEITEM='D' OR CODEITEM='W'

现在它给我带来了两列门，窗，同样的结果

我真正想要的是在DOORS列上只显示代码为“D”的项目，在WINDOWS列上只显示代码为“W”的项目

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我如何才能做到这一点？

您似乎想要：

SELECT numero, 
       MAX(CASE WHEN CODEITEM = 'D' THEN N2 END) AS DOORS,
       MAX(CASE WHEN CODEITEM = 'W' THEN N2 END) AS WINDOWS
FROM DATABASE.dbo.DISTINTAB
WHERE numero = 45 AND CODEITEM IN ('D', 'W')
GROUP BY numero; 

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您可以在选择时使用案例

SELECT 
  (CASE WHEN codeitem = 'D' THEN N2 ELSE NULL END) AS DOORS, 
  (CASE WHEN codeitem = 'W' THEN N2 ELSE NULL END) AS WINDOWS
FROM DATABASE.dbo.DISTINTAB
WHERE numero = 45 AND codeitem IN ('D', 'W')

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您可以使用此查询

用于同一行中显示的结果的聚合函数

SELECT numero, 
       MAX(CASE WHEN CODEITEM = 'D' THEN CODEITEM ELSE '' END ) AS DOORS,
       MAX(CASE WHEN CODEITEM = 'W' THEN CODEITEM ELSE '' END) AS WINDOWS
FROM DISTINTAB
WHERE numero = 45 AND CODEITEM IN ('D', 'W')
GROUP BY numero; 

通常情况下，当numero时，codeitem不定义为唯一：

WITH cte AS 
(
SELECT n2, ROW_NUMBER() OVER (PARTITION BY codeitem ORDER BY NULL) rn
FROM DATABASE.dbo.DISTINTAB
WHERE numero=45
  AND codeitem IN ('D', 'W')
)
SELECT t1.n2 as Doors, t2.n2 as Windows
FROM cte t1
FULL OUTER JOIN cte t2 ON t1.rn= t2.rn

如果上述字段组合定义为唯一，则

SELECT t1.n2 as Doors, t2.n2 as Windows
FROM DATABASE.dbo.DISTINTAB t1
FULL OUTER JOIN DATABASE.dbo.DISTINTAB t2 
    ON t1.numero=45
   AND t2.numero=45
   AND t1.codeitem = 'D'
   AND t2.codeitem = 'W'

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向我们展示一些示例表数据和预期结果。作为格式化文本，而不是图像。@Akina谢谢，我已经编辑过了。您将获得2条记录。是的，您可能会获得多条记录，这取决于您的数据。非常感谢。你是最终的解决方案+1.