SQL生成每个组内的序列号

Question

 PO NO     Acc No    ResultSeqNo
    A1           12          1 
    A1           12          1
    A1           12          1
    A1           12          1
    A2           12          2 
    A2           12          2
    A2           12          2
    A3           13          1
    A3           13          1
    A4           13          2 
    A4           13          2
    A5           14          1 

In above table, PONO and AccNo are related, SeqNo is nothing but the Counter in the flag. I need to group by PONo and Accno.

If you see in the above table, A1 and A2 has same account number , but all A1 is considered to be a single group, so the seqNo should be 1 for all A1. A2 also has the same acc no as A1, but it's a different group, so it should have the seq No 2.

Put another way: for each AccNo number, I need to generate sequence numbers by PO NO. So for Account #12, all of the A1 PO NO records have sequence 1, and all of the A2 PO NO records have sequence 2. For account 13, A3 is 1 and A4 is 2.

Here is what I have so far:

UPDATE x 
SET x.ResultSeqNo = x.dr 
FROM 
  (
    SELECT SeqNo,dense_rank() over (order by PO NO) as dr 
    FROM [Purchaseorder] 
    WHERE status = 'In'
  ) x

Answer 1

您需要使用dense_rank分析函数，但添加一个partition by子句来对集合进行分组以生成序列号，例如:

SELECT dense_rank() OVER (PARTITION BY acc_no ORDER BY po_no)