如何在同一个表中用不同的条件检索同一列两次？ [英] How to retrieve same column twice with different conditions in same table?

问题描述

这是我的表：

Anganbadi_ID               Food     Month
-------------------------------------------    
1165                       हाँ         1
1165                       हाँ         2
1165                       हाँ         4
1168                       हाँ         4
2032                       नहीं        4
2218                       नहीं        4
2219                       हाँ         4
2358                       नहीं        4
2546                        हाँ        10 

有4列 Anganbadi_ID，Food，Month，Year 希望根据两个不同的月份值比较 Food 列两次。

there are 4 columns Anganbadi_ID, Food, Month, Year and I want to compare Food column twice based on two different month values.

例如如果我为第一个Food（Food-1）栏选择Month = 4，第二个Food（Food-2）栏选择Month = 10，则应该如下所示::

e.g. if I select Month=4 for first Food (Food-1) column and Month=10 for second Food (Food-2) column, then it should be like following::

Anganbadi_ID            Food-1     Food-2    
------------------------------------------    
1165                       हाँ          NULL 
1168                       हाँ          NULL 
2032                       नहीं        NULL 
2218                       नहीं        NULL 
2219                       हाँ          NULL 
2358                       नहीं        NULL 
2546                     NULL        हाँ 

当我尝试此代码

SELECT     
   Anganbadi_ID, Food,
   (SELECT Food
    FROM Anganbadi AS Anganbadi_2
    WHERE (Anganbadi_1.Anganbadi_ID = Anganbadi_ID) 
      AND (Anganbadi_1.Month = 10)
   ) AS 'Food(2)'
FROM Anganbadi AS Anganbadi_1
WHERE (Month = 4)

它显示以下结果：

Anganbadi_ID              Food-1     Food-2    
--------------------------------------------
1165                       हाँ          NULL 
1168                       हाँ          NULL 
2032                       नहीं        NULL 
2218                       नहीं        NULL 
2219                       हाँ          NULL 
2358                       नहीं        NULL 

请尽快帮助我....

Please help me as soon as possible....

推荐答案

SELECT DISTINCT Anganbadi_ID,

(SELECT Food 
 FROM Anganbadi 
 WHERE      (Anganbadi_ID = A.Anganbadi_ID) 
    AND (Month = 4)) AS Food1,

(SELECT Food 
 FROM Anganbadi 
 WHERE      (Anganbadi_ID = A.Anganbadi_ID) 
    AND (Month = 10)) AS Food2

FROM Anganbadi AS A 
WHERE A.Month = 10 OR A.Month = 4

SQL小提琴

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