[英]How to combine each three rows into single column in SQL Server 2008?
NOOfDays DISTRInutorID
-------------------------
1 abcd
1 cdef
2 DFSDF
2 SFSDD
2 SDFSD
2 WAOYWAR
7 WEFIWE
7 WEOFYWE
7 WFYREU
以上是我的示例表之一,我想根據 NOOfDays 組合每兩行。
預期 output:
NOOfDays DiSTRInutorID
------------------------------
1 abcd, cdef
2 DFSDF, SFSDD
2 SDFSD, WAOYWAR
7 WEFIWE, WEOFYWE
7 WFYREU
在SQL服務器的古代版本中,邏輯如下:
select n.NOOfDays,
stuff( (select ',' + t2.DISTRInutorID
from t t2
where t2.NOOfDays = n.NOOfDays
for xml path ('')
), 1, 1, ''
) as list
from (select distinct NOOfDays from t) n;
編輯:
我誤解了原來的問題。 這就是您要查找的內容:
with cte as (
select t.*, row_number() over (order by (select null)) - 1 as seqnum
from t
)
select NOOfDays,
(case when count(*) = 1 then min(DISTRInutorID)
else max(case when seqnum % 2 = 0 then DISTRInutorID end) + ',' + max(case when seqnum % 2 = 1 then DISTRInutorID end)
end) as list
from cte
group by NOOfDays, floor(seqnum / 2);
請注意,SQL 表表示無序集。 這會任意配對第一列相同的行,但不能保證它們是相鄰的——原因很簡單,“相鄰”沒有定義。
這是一個 db<>fiddle。
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