有问题的sql server查询

我有以下运行缓慢的查询：

 WITH AcdTran
     AS (select SequenceNo,
                ReqID,
                PolNumber,
                transaction_id,
                application_data,
                trans_type,
                retries,
                status,
                direction
         from   dbo.acord_transaction_benchmark with (nolock)
         where  direction = 'OUT')
select top 1 *
from   AcdTran a
where  a.transaction_id = (select top 1 transaction_id
                           from   AcdTran b
                           where  b.PolNumber = a.PolNumber
                           order  by ReqID,
                                     SequenceNo,
                                     transaction_id)
       and ( status = 'New'
              or status = 'Resubmit' )
       and retries > 0  

我如何优化它？跑得更快

---

谢谢

使用窗口功能行数应该会更快：

 WITH AcdTran AS (
         SELECT SequenceNo,
                ReqID,
                PolNumber,
                transaction_id,
                application_data,
                trans_type,
                retries,
                status,
                direction,
                ROW_NUMBER() OVER(PARTITION BY transaction_id ORDER BY ReqID, SequenceNo, transaction_id) N
           FROM dbo.acord_transaction_benchmark with (nolock)
          WHERE direction = 'OUT')
SELECT *
  FROM AcdTran
 WHERE (status = 'New'
            OR status = 'Resubmit')
       AND retries > 0
       AND N = 1;

---

由于我没有您的表结构或任何数据，我显然没有对其进行测试，因此您可能需要稍微修改查询，但您有这个想法。

如果您将子查询拖出到联接中会怎么样：

WITH AcdTran
     AS (select SequenceNo,
                ReqID,
                PolNumber,
                transaction_id,
                application_data,
                trans_type,
                retries,
                status,
                direction
         from   dbo.acord_transaction_benchmark with (nolock)
         where  direction = 'OUT')
select top 1 *
from   AcdTran a
inner join AcdTran b on a.SequenceNo = b.SequenceNo --or whatever the PK is
where a.transaction_id = b.transaction_id and
      a.PolNumber = b.PolNumber and
      (a.status = 'New' or a.status = 'Resubmit' ) and
      a.retries > 0
order by b.ReqID,
         b.SequenceNo,
         b.transaction_id

---

它应该做什么？您的

select top 1*

缺少一条

order by

它应该选择一条状态为New的记录，或者按顺序从表中重新提交。因此，如果我有2条记录，其中一条记录有序列1，另一条记录有序列2，那么应该选择序列为1OK的记录，我认为这只是一个标准的

最大n-每组

查询。有3种方法。最好的方法取决于你的索引和数据分布。你可能已经有了，但要确保你把索引放在了正确的列上。它对这类问题有很大的影响queries@JustMe你能提供一些示例数据和期望的结果吗？JustMe:我的错误，应该是

按事务划分\u id

，我编辑了我的帖子。