SQL在表中显示重复值

Question

我需要获得一个查询，该查询将显示具有相同银行详细信息且已被错误捕获的人员的详细信息。

我需要然后显示正确的细节以及这些人的不正确的细节。例如：

 
1stName 1stAccNo 1stItemSold 2ndName 2ndAccNo 2ndItemSold 
Albert 2231432  Item1   John  2231432 Item3 
Robert09  Item11  Peter09 Item3 

名称和AccNo在一张桌子上，而ItemSold在不同的桌子上。

我有以下查询：

select p1.Name As 1stName, p1.AccNo AS 1stAccNo, I.ItemSold AS 1stItemSold, p2.Name AS 2ndName, p2.AccNo AS 2ndAccNo, I.ItemSold As 2ndItemSold 
FROM Persons p1 JOIN Persons p2 ON p1.AccNo = p2.AccNo 
INNER JOIN Items I on p.ItemID = I.ItemID 

的问题是，第二ItemSold是不正确的，因为它是一样的1stItemSold。我该如何改变我的查询，以便我可以获得正确的结果？

Answer 1

您应该将项目加入第二个表格。此外，如果你需要不同的人，你必须包含where p1.id<>p2.id其中ID是在人员表的主键

select 
p1.Name As 1stName, p1.AccNo AS 1stAccNo, I1.ItemSold AS 1stItemSold, 
p2.Name AS 2ndName, p2.AccNo AS 2ndAccNo, I2.ItemSold As 2ndItemSold 
FROM Persons p1 JOIN Persons p2 ON p1.AccNo = p2.AccNo 
INNER JOIN Items I1 on p1.ItemID = I1.ItemID 
INNER JOIN Items I2 on p2.ItemID = I2.ItemID 
where p1.id<>p2.id 

PS：基于评论。返回最后ItemSold避免重复：

select 
p1.Name As 1stName, p1.AccNo AS 1stAccNo, I1.ItemSold AS 1stItemSold, 
p2.Name AS 2ndName, p2.AccNo AS 2ndAccNo, I2.ItemSold As 2ndItemSold 
FROM Persons p1 JOIN Persons p2 ON p1.AccNo = p2.AccNo 
left JOIN 
    (select ItemID,ItemSold, 
      row_number() over (PARTITION BY ItemID order by DATE_SOLD DESC) as rn 
    from Items) I1 
     on (p1.ItemID = I1.ItemID) and (rn=1) 
left JOIN 
    (select ItemID,ItemSold, 
      row_number() over (PARTITION BY ItemID order by DATE_SOLD DESC) as rn 
    from Items) I2 
     on (p2.ItemID = I2.ItemID) and (rn=1) 

where p1.id<>p2.id 

Answer 2

我可能会误解你的要求，但它听起来像是你可以使用UNPIVOT/PIVOT功能得到你需要的结果。

如果您知道要转换的列数，那么您可以对此静态版本进行硬编码。

select * 
from 
(
    select AccNo, 
    val, 
    col + cast(rn as varchar(10)) Col_Name 
    from 
    (
    select p1.accno, 
     p1.name, 
     p1.itemid, 
     i1.id, 
     i1.i_name, 
     row_number() over(partition by accno order by name) rn 
    from persons p1 
    left join items i1 
     on p1.itemid = i1.id 
) x 
    unpivot 
    (
    val 
    for col in (name, i_name) 
) u 
) x1 
pivot 
(
    max(val) 
    for col_name in ([name1], [i_name1], [name2], [i_name2]) 
) p 

看到SQL Fiddle with Demo

但它听起来像是你将有数目不详的项目转变为列，因此你可以使用动态SQL和创造的这一动态的版本：

DECLARE @colsUnPivot AS NVARCHAR(MAX), 
    @colsPivot AS NVARCHAR(MAX), 
    @query AS NVARCHAR(MAX) 

SET @colsUnPivot = stuff((select ','+C.name 
     from sys.columns as C 
     where (C.object_id = object_id('persons') 
        or C.object_id = object_id('items')) 
      and C.name like '%name%' 
     for xml path('')), 1, 1, '') 

select @colsPivot = STUFF((SELECT ',' 
         + quotename(c.name 
         + cast(p.rn as varchar(10))) 
        from 
        (
         select row_number() over(partition by accno order by name) rn 
         from persons 
        ) p 
        cross apply 
         sys.columns as C 
        where (C.object_id = object_id('persons') 
          or C.object_id = object_id('items')) 
         and C.name like '%name%' 
        group by c.name, p.rn 
        order by p.rn, c.name desc 
      FOR XML PATH(''), TYPE 
      ).value('.', 'NVARCHAR(MAX)') 
     ,1,1,'') 

set @query 
    = 'select * 
     from 
     (
      select AccNo, 
      val, 
      col + cast(rn as varchar(10)) Col_Name 
     from 
     (
      select p1.accno, 
      p1.name, 
      p1.itemid, 
      i1.id, 
      i1.i_name, 
      row_number() over(partition by accno order by name) rn 
      from persons p1 
      left join items i1 
      on p1.itemid = i1.id 
     ) x 
     unpivot 
     (
      val 
      for col in ('+ @colsunpivot +') 
     ) u 
    ) x1 
     pivot 
     (
     max(val) 
     for col_name in ('+ @colsPivot + ') 
    )p' 

exec(@query) 

请参阅SQL Fiddle with Demo