Question

我有36个Sales表，每个表都指向一个商店：

st1.dbo.Sales  
st2.dbo.Sales  
...  
st35.dbo.Sales  
st36.dbo.Sales

每条记录都有以下关键列：

UserName, PostalCode, Location, Country, InvoiceAmount, ItemsCount, StoreID

这是SQLFiddle

我需要将Customers

中尚未出现的所有用户名（及其详细信息）复制到Customers表中

如果重复，则需要使用InvoiceAmount为MAX

的记录字段

我尝试构建一个查询，但看起来太复杂了，这也是错误的，因为在CROSS APPLY中应该考虑Sales表的完整列表

INSERT INTO Customers (.....)
    SELECT distinct 
        d.UserName, 
        w.postalCode, 
        w.location, 
        W.country,  
        max(w.invoiceamount) invoiceamount, 
        max(w.itemscount) itemscount,
        w.storeID
    FROM 
        (SELECT * FROM st1.dbo.Sales
         UNION              
         SELECT * FROM st2.dbo.Sales
         UNION
         ...
         SELECT * FROM st36.dbo.Sales) d
    LEFT JOIN 
        G.dbo.Customers s ON d.Username = s.UserName
    CROSS APPLY 
        (SELECT TOP (1) * 
         FROM s.dbo.[Sales]  
         WHERE d.Username=w.Username
         ORDER BY InvoiceAmount DESC) w
    WHERE 
        s.UserName IS NULL
        AND d.username IS NOT NULL
    GROUP BY 
        d.UserName, w.postalCode, w.location,    
        w.country, w.storeID

有人可以提供一些提示吗？

Answer 1

作为基本的SQL查询，我在内部子查询中创建一个row_number，然后加入客户，然后隔离不在客户表中的每个客户的最大发票编号。

INSERT INTO Customers (.....)
    SELECT w.UserName, 
        w.postalCode, 
        w.location, 
        w.country,  
        w.invoiceamount, 
        w.itemscount,
        w.storeID
    FROM (select d.*,
              row_number() over(partition by d.Username order by d.invoiceamount desc) rownumber 
          from  (SELECT * 
                 FROM st1.dbo.Sales
                 UNION              
                 SELECT * 
                 FROM st2.dbo.Sales
                 UNION
                 ...
                 SELECT * 
                 FROM st36.dbo.Sales
                ) d 
           LEFT JOIN G.dbo.Customers s 
               ON d.Username = s.UserName
           WHERE s.UserName IS NULL
               AND d.username IS NOT NULL
         ) w
    where w.rownumber = 1

Answer 2

使用您的小提琴，这将选择具有最大invoiceamount

的不同用户名行

with d as(
  SELECT * FROM Sales
  UNION              
  SELECT * FROM Sales2
)
select *
from ( select *, 
      rn = row_number() over(partition by Username order by invoiceamount desc)
      from d) dd
where rn=1;

Answer 3

第1步 - 使用cte。

                select  username , invoiceamount ,itemscount from Sales
          UNION all
               select  user name , invoiceamount ,itemscount from Sales

.....

...

第2步

next cte使用group by并获取max invoiceamount，itemscount为最后结果集的用户。

         ,cte2 as (

      select  user name , max (invoiceamount) as invoiceamount  ,max(itemscount) as itemscount  from  cte)

第3步

使用左连接和用户表，找到缺少的记录和itemscount invoiceamount

SQL Server 2014合并表避免重复

3 个答案: