我该如何创建这个T-SQL子查询？

Question

我在这里失去了联系。在过去，我会想出一个超级T-SQL查询，

Select t1.Number, t1.TransactionType, t1.Description, t1.Vendor,
(Select max(t2.BatchId) From table2 t2
 Where t1.Number=t2.Number and t1.TransactionType=t2.TransactionType
 Group By t2.number,t2.transactiontype) As BatchId
From table1 t1

我需要table2中的第二列。列称为“结果”。

示例：

table1:
Number, TransactionType, Description, Vendor
1, Type1, Test1, Vendor1
2, Type1, Test2, Vendor2
1, Type2, Test3, Vendor3
3, Type2, Test1, Vendor2

table2:
Number, TransactionType, BatchId, Result
1, Type1, 12, error1
1, Type1, 4, error2
1, Type2, 8, success
3, Type2, 7, success

wanted ResultSet:
Number, TransactionType, Description, Vendor, BatchId, Result
1, Type1, Test1, Vendor1, 12, error2
2, Type1, Test2, Vendor2, null, null
1, Type2, Test3, Vendor3, 8,success
3, Type2, Test1, Vendor2, 7,success

发布的查询负责前5列。那最后一栏怎么样？

Answer 1

select t1.Number, t1.TransactionType, t1.Description, t1.Vendor, t2.BatchId, t2.Result
from table1 t1
left join
(
  select t2.TransactionType, t2.number, t2.Result, t2.BatchId,
    row_number() over (partition by t2.number, t2.TransactionType order by t2.BatchId desc) as BatchNumber
  from table2 t2
) t2 on t1.Number = t2.Number
  and t1.TransactionType = t2.TransactionType
  and t2.BatchNumber = 1

如果你可以确定t1中的每一行都有t2中的相关行，那么用内连接替换左连接会更好。

UPD 在评论中发现了错误。我已将查询更改为正确的版本。