Question

我想加入两个表来创建一个决赛桌。

查询1

select DisplayName, Category, NoOfLevels
, count(Underoverestimate) as OverCount
, Avg(CaseDuration - EstDuration) as ODA
from DSU
where yearid between '2016' and '2018'
and underoverestimate = 'Over'
group by DisplayName, Category, nooflevels

查询2

select DisplayName, Category, NoOfLevels
, count(Underoverestimate) as UnderCount
, Avg(CaseDuration - EstDuration) as ODA
from DSU
where yearid between '2016' and '2018'
and underoverestimate = 'Under'
group by DisplayName, Category, nooflevels

查询1结果

DisplayName|Category     |NoOfLevels|OverCount|ODA
Bran, J.   |Fusion       |Single    |2        |102.5
Bran, J.   |Decompression|          |1        |13
Caron, M.  |Fusion       |Multi     |9        |88.444

查询2结果

DisplayName|Category     |NoOfLevels|UnderCount|ODA
Curry, S.  |Fusion       |Multi     |2        |105
Bran, J.   |Fusion       |Single    |1        |115.5
Bran, J.   |Decompression|          |4        |131
Caron, M.  |Decompression|          |5        |66

我希望最终结果是保留所有唯一的DisplayName，Catergory和NoOfLevels，但添加＆＃39; OverCount＆＃39;和来自查询1和＆＃39; UnderCount＆＃39;的官方发展援助和ODA＆＃39;来自查询2.

通缉的最终结果

DisplayName|Category     |NoOfLevels|OverCount|ODA    |UnderCount|ODA
Bran, J.   |Fusion       |Single    |2        |102.5  |1         |115.5
Bran, J.   |Decompression|          |1        |13     |4         |131
Caron, M.  |Decompression|          |         |       |5         |66
Caron, M.  |Fusion       |Multi     |9        |88.444 |          |
Curry, S.  |Fusion       |Multi     |         |       |5         |66

我尝试通过创建带有查询1和2的临时表，然后创建一个新的select语句来报告我想要的数据。

Select #QueryOne.DisplayName, #QueryOne.Category, 
#QueryOne.NoOfLevels, count(#QueryTwo.UnderCount) as UnderCount
from #QueryOne
join #QueryTwo
on #QueryOne.DisplayName = #QueryTwo.DisplayName
group by #QueryOne.DisplayName, #QueryOne.Category, 
#QueryOne.NoOfLevels
order by #QueryOne.DisplayName, #QueryOne.Category, 
#QueryOne.NoOfLevels

我的结果是错误的。（我还在测试查询，所以我没有包含我想要的所有列，但在测试中我注意到结果是错误的）

DisplayName|Category     |NoOfLevels|UnderCount|
Bran, J.   |Fusion       |Single    |6         |
Caron, M.  |Fusion       |Multi     |9         |
Bran, J.   |Decompression|          |6         |
Curry, S.  |Fusion       |Multi     |12        |
Caron, M.  |Decompression|          |9         |

前3列看起来正确，但是＆＃39; UnderCount＆＃39;值不正确。＆＃39; COUNT＆＃39;此查询中的函数给出了Bran的总行数。使用＆＃39; SUM＆＃39;导致错误的信息。最后，如果我删除＆＃39; COUNT（＆＃39;那么我需要将＃QueryTwo.UnderCount放入组中，以便给出以下结果：

DisplayName|Category     |NoOfLevels|UnderCount|
Bran, J.   |Fusion       |Single    |1         |
Bran, J.   |Fusion       |Single    |2         |
Bran, J.   |Decompression|          |1         |
Bran, J.   |Decompression|          |2         |
Caron, M.  |Decompression|          |3         |
Caron, M.  |Decompression|          |2         |
Caron, M.  |Fusion       |Multi     |3         |
Caron, M.  |Fusion       |Multi     |1         |

我已经尝试通过stackoverflow寻找这个答案，但是没有找到类似的问题，我发现很多问题要求加入两张桌子，但他们的问题不一样......我和＃ 39;我考虑过UNION，但如果下一步是正确的话我似乎无法理解。我认为问题的一部分是查询1的DisplayNames不在查询2中，反之亦然。难以加入??

如果我需要澄清更多，请告诉我，我的大脑很难。

Answer 1

尝试使用full join从两个表中获取所有唯一的DisplayName，Category，NoOfLevels行

select *
from (query1) t1 
full join (query2) t2 
    on t1.DisplayName = t2.DisplayName
    and t1.Category = t2.Category
    and t1.NoOfLevels = t2.NoOfLevels

另一种可能的解决方案是使用不带连接的条件聚合

select DisplayName, Category, NoOfLevels
, count(case when underoverestimate = 'Over' then Underoverestimate end) as OverCount
, count(case when underoverestimate = 'Under' then Underoverestimate end) as UnderCount
, Avg(case when underoverestimate = 'Over' then CaseDuration - EstDuration end) as ODA
, Avg(case when underoverestimate = 'Under' then CaseDuration - EstDuration end) as UDA
from DSU
where yearid between '2016' and '2018'
and underoverestimate IN ( 'Over' , 'Under' )
group by DisplayName, Category, nooflevels

Answer 2

您可以使用完整联接从两个表中获取结果。有关详细信息，请访问https://www.w3schools.com/sql/sql_join_full.asp

SELECT
  *
FROM (SELECT
  DisplayName,
  Category,
  NoOfLevels,
  COUNT(Underoverestimate) AS OverCount,
  AVG(CaseDuration - EstDuration) AS ODA
FROM DSU
WHERE yearid BETWEEN '2016' AND '2018'
AND underoverestimate = 'Over'
GROUP BY DisplayName,
         Category,
         nooflevels) a
FULL OUTER  JOIN (SELECT
  DisplayName,
  Category,
  NoOfLevels,
  COUNT(Underoverestimate) AS UnderCount,
  AVG(CaseDuration - EstDuration) AS ODA
FROM DSU
WHERE yearid BETWEEN '2016' AND '2018'
AND underoverestimate = 'Under'
GROUP BY DisplayName,
         Category,
         nooflevels) b
  ON a.DisplayName = b.DisplayName
  AND a.Category = b.Category
  AND a.NoOfLevels = b.NoOfLevels

合并SQL Server

2 个答案: