我有一张桌子,其中包含一位丈夫对妻子的真实情况。
该表包含每行两个行(BTW,性别没有意义。可能是丈夫 - 丈夫和妻子 - 妻子。只是说)。意思是,该表可能显示"连接"的两行结果:
Wife--Husband
和\或Husband--Wife
该表如下所示:
Id1 | Id2 | ConnectiondID | RelatedConnectionId
-----------------------------------------------------
123 | 333 | FF45 | F421
333 | 123 | F421 | FF45
456 | 987 | F333 | F321
987 | 456 | F321 | F333
我的预期结果是每组只有一个关系:
Id1 | Id2
----------
123 | 333
456 | 987
答案 0 :(得分:1)
这实际上非常简单,假设您只想要情侣,并且您的ID
值都是唯一且数字的,并且不需要任何自联接,功能或分组:
declare @t table(Id1 int,Id2 int,ConnectiondID nvarchar(5),RelatedConnectionId nvarchar(5));
insert into @t values(123,333,'FF45','F421'),(333,123,'F421','FF45'),(456,444,'FF46','F422'),(444,456,'F422','FF46'),(789,555,'FF47','F423'),(555,789,'F423','FF47');
select *
from @t
where Id1 < Id2
order by Id1
输出:
+-----+-----+---------------+---------------------+
| Id1 | Id2 | ConnectiondID | RelatedConnectionId |
+-----+-----+---------------+---------------------+
| 123 | 333 | FF45 | F421 |
| 444 | 456 | F422 | FF46 |
| 555 | 789 | F423 | FF47 |
+-----+-----+---------------+---------------------+
答案 1 :(得分:0)
如果我正确理解您的问题,您需要在桌面上执行自我加入,例如ON t1.id1 = t2.id2
或ON t1.ConnectionId = t2.RelatedConnectionID
,显然这是两种方式。
要将此限制为仅一种方式,请在连接谓词上添加条件,使其中一个值小于或大于另一个值; e.g。
DECLARE @tbl table( Id1 smallint PRIMARY KEY, Id2 smallint,ConnectiondID char(5),RelatedConnectionId char(5));
INSERT @tbl(Id1,Id2,ConnectiondID,RelatedConnectionId)
VALUES(123,333,'FF45','F421'),
(333,123,'F421','FF45'),
(456,222,'FF45','F421'),
(222,456,'F421','FF45'),
(789,111,'FF45','F421'),
(111,789,'F421','FF45');
SELECT *
FROM @tbl t1
JOIN @tbl t2 ON t2.Id1 = t1.Id2 AND t2.Id1 > t1.Id1;
答案 2 :(得分:0)
例如
DECLARE @T TABLE (id1 int, id2 int,ConnectiondID varchar(5),RelatedConnectionId varchar(5) )
INSERT INTO @T (Id1,Id2,ConnectiondID,RelatedConnectionId)
VALUES
(123 , 333 ,'FF45','F421'),
(333 , 123 , 'F421','FF45'),
(2123 , 2333 ,'2FF45','2F421'),
(2333 , 2123 , '2F421','2FF45'),
(3 , 2 , 'AAAA','BBB'),
(2 , 3 , 'BBB','AAAA')
SELECT
a.*
FROM
@t a
WHERE
CASE
WHEN ConnectiondID > RelatedConnectionId
THEN RelatedConnectionId
ELSE NULL
END IS NULL