Question

我有一张表MBR_Role。现在它有成员ID作为键（主要约束）。对应于每个成员id，可以基于两个指标来存在不同类型的地址。我有两个指标，Ind1和Ind2。所以我的表就像 -

Mbr ID  Ind1    Ind2    Country City    Postal_code
1   Y   N   UK  London  11111
1   N   Y   Spain   Madrid  22222
1   N   N   US  New York    33333
2   Y   N   France  Paris   44444

指标1给出住址，指标2给出办公地址。我希望每个成员的结果中都有这些地址（基于指标）。

所以，我的结果应该是 -

Mbr ID  Country     City    Postal_code Legal Country    Legal City Legal Postal_code
1   UK  London  11111               Spain          Madrid     22222
2   France  Paris   44444

有关如何实现这一目标的任何帮助？

Answer 1

这是一个可能的解决方案（MySQL）

CREATE TABLE MBR_Role(
   Mbr_ID INT,
   Ind1 VARCHAR(1),
   Ind2 VARCHAR(1),
   Country VARCHAR(30),
   City VARCHAR(30),
   Postal_code VARCHAR(30));

INSERT INTO MBR_Role VALUES (1, "Y", "N", "UK",  "London",  "11111");
INSERT INTO MBR_Role VALUES (1, "N", "Y", "Spain",  "Madrid",  "22222");
INSERT INTO MBR_Role VALUES (1, "N", "N", "US",  "New York",  "33333");
INSERT INTO MBR_Role VALUES (2, "Y", "N", "France",  "Paris",  "44444");

我使用左外连接来处理不存在地址的情况。

select a.Mbr_ID,
       b.Country, b.City, b.Postal_code,
       c.Country as legal_country, c.City as legal_city, c.Postal_code as legal_Postal_code
from (select distinct Mbr_ID from MBR_Role) as a
LEFT OUTER JOIN MBR_Role b ON (b.Mbr_ID = a.Mbr_ID AND b.Ind1 = "Y" AND b.Ind2 = "N"  )
LEFT OUTER JOIN MBR_Role c ON (c.Mbr_ID = a.Mbr_ID AND c.Ind1 = "N" AND c.Ind2 = "Y"  );

它为您提供期待已久的结果。链接到sqlfiddle http://sqlfiddle.com/#!2/a2ecb/9

无论如何，就像其他人告诉你的那样，我认为如果可能的话，你应该尝试重新设计你的桌子。

在外部查询中显示嵌套查询结果

1 个答案: