MS Access，Inventory Levels查询耗时太长。备择方案？

Question

我有一张桌子可以生成许多SKU的每日更改。 它还增加0，因为报告需要它们。

目前生成大约60,000条数据记录，如下图所示：

然后我有一个如下所示的查询：

SELECT t1.Date, t1.[Part SKU], t1.[SKU Name], t1.[Inventory Change], (SELECT SUM(t2.[Inventory Change]) 
    FROM [Inventory Report Table] t2
    WHERE t1.[Date] >= t2.[Date]
    AND t1.[Part SKU] = [t2.Part SKU]) AS [Inventory Level]
FROM [Inventory Report Table] AS t1
ORDER BY t1.Date, t1.[Part SKU];

此查询的基本操作是它根据零件SKU汇总所有记录，其中日期＆gt; =该SKU的日期。

给出这样的结果：

问题是，这需要太长时间。 我一直试图为此找到解决方法......

但我被困了

Answer 1

这是您的查询：

SELECT t1.Date, t1.[Part SKU], t1.[SKU Name], t1.[Inventory Change],
       (SELECT SUM(t2.[Inventory Change]) 
        FROM [Inventory Report Table] t2
        WHERE t1.[Date] >= t2.[Date] AND t1.[Part SKU] = [t2.Part SKU]
       ) AS [Inventory Level]
FROM [Inventory Report Table] AS t1
ORDER BY t1.Date, t1.[Part SKU];

为了提高性能，我会尝试以下两个索引：[Inventory Report Table](Date, [Part SKU])和[Inventory Report Table]([Part SKU], Date)。是的，两者都是可取的，一个用于子查询，一个用于外部查询。

这可能会有所帮助。但是，您真正需要累积和功能。您可以考虑升级到提供此功能的SQL Server或Postgres等数据库。

Answer 2

可以是：

SELECT t1.DATE
    ,t1.[Part SKU]
    ,t1.[SKU Name]
    ,t1.[Inventory Change]
    ,SUM(t2.[Inventory Change])  AS [Inventory Level]

FROM [Inventory Report Table] AS t1
left join [Inventory Report Table] t2
on t1.[Part SKU] = [t2.Part SKU]

WHERE t1.[Date] >= t2.[Date]

group by t1.DATE
    ,t1.[Part SKU]
    ,t1.[SKU Name]
    ,t1.[Inventory Change]

ORDER BY t1.DATE
    ,t1.[Part SKU];

PS：我还没有测试查询，这只是一个想法。