Question

我有以下查询（我们称之为Query1）（由here友好创建Erik von Asmuth）：

SELECT PARTNERID
    ,NAME
    ,FIRST_NAME
    ,UID
    ,DATA_R
FROM MY_TABLE
WHERE MY_TABLE.[DATA_R] = (
        SELECT MAX(t.[DATA_R])
        FROM MY_TABLE AS t
        WHERE t.PARTNERID = MY_TABLE.PARTNERID
        )
ORDER BY PARTNERID;

MY_TABLE有20000个记录，并且是一个查询（即使名称可能暗示相反），使用以下格式：

SELECT [MYTABLE_O].PARTNERID, [MYTABLE_O].NAME, [MYTABLE_O].FIRST_NAME, [MYTABLE_O].[Codice fiscale] AS CF, [MYTABLE_O].Date AS DATA_R
FROM [MYTABLE_O] LEFT JOIN [TO_EXCLUDE] ON [MYTABLE_O].[PARTNERID] = [TO_EXCLUDE].[PARTNERID]
WHERE ((([TO_EXCLUDE].PARTNERID) Is Null));

（我想排除表TO_EXCLUDE中已经考虑过的一些元素。）

当我运行查询（Query1）时，MS Access会冻结。如何避免它/使其更有效和稳定？

我尝试在MYTABLE_O和PARTNERID

中DATA_R进行索引

Answer 1

您可能必须编写子查询的结果：

SELECT PARTNERID, MAX([DATA_R]) AS MAXDATAR
FROM YourQuery
GROUP BY PARTNERID

到临时表，然后在查询中替换

FROM MY_TABLE AS t

与

FROM TempTable AS t

访问：查询崩溃

1 个答案: