Question

我需要根据三个条件选择数据

从表中查找每条记录的最新日期（StorageDate列）
查看相同ID（ID列）的第一步中是否有多个日期条目（StorageDate列）
然后查看DuplicateID是否为= 2

因此，如果表格包含以下数据：

ID   |StorageDate | DuplicateTypeID
1    |2014-10-22  | 1
1    |2014-10-22  | 2
1    |2014-10-18  | 1
2    |2014-10-12  | 1
3    |2014-10-11  | 1
4    |2014-09-02  | 1
4    |2014-09-02  | 2

然后我应该得到以下结果

ID  
1
4

我写过以下查询，但它确实很慢，我想知道是否有人有更好的方法来编写它。

SELECT DISTINCT(TD.RecordID)
FROM dbo.MyTable TD
JOIN (
    SELECT T1.RecordID, T2.MaxDate,COUNT(*) AS RecordCount
    FROM MyTable T1 WITH (nolock) 
    JOIN (
    SELECT RecordID, MAX(StorageDate) AS MaxDate
            FROM MyTable WITH (nolock)
            GROUP BY RecordID)T2 
    ON T1.RecordID = T2.RecordID AND T1.StorageDate = T2.MaxDate
    GROUP BY T1.RecordID, T2.MaxDate
    HAVING COUNT(*) > 1
    )PT ON TD.RecordID = PT.RecordID AND TD.StorageDate = PT.MaxDate
    WHERE TD.DuplicateTypeID = 2

Answer 1

您可以使用分析函数rank，您可以尝试此查询吗？

Select recordId from
(
  select *, rank() over ( partition by recordId order by [StorageDate] desc) as rn 
  from mytable
) T
where rn =1
group by recordId
having count(*) >1
and sum( case when duplicatetypeid =2 then 1 else 0 end) >=1

Answer 2

试试这个，看看性能如何：

;WITH
    tmp AS
    (
        SELECT      *,
                    RANK() OVER (PARTITION BY ID ORDER BY StorageDate DESC) AS StorageDateRank,
                    COUNT(ID) OVER (PARTITION BY ID, StorageDate) AS StorageDateCount
        FROM        MyTable
    )

SELECT DISTINCT ID
FROM tmp
WHERE StorageDateRank = 1   -- latest date for each ID
  AND StorageDateCount > 1  -- more than 1 entry for date
  AND DuplicateTypeID = 2   -- DuplicateTypeID = 2

编写此SQL查询的任何其他替代方法

2 个答案: