Question

Name      ExactDate  Presents      Location
bob1         2011        1          home
bob2         2008        2          school     
bob2         2012        3          school
mary2        1986        4          school       
mary1        2001        5          home
mary1        2012        6          home    
kate1        2011        7          home
kate1        2012        8          home
kate2        2011        9          school 
celia2       2011       10          school 
celia2       1986       11          school  
celia1       1972       12          home
celia1       2012       14          home 
celia2       2012       13          school

此问题在MS Access 2003中用于查询的SQL中完成。

所以我们的目标是减去凯特在同一年从凯里亚那里得到的礼物数量（但由于同年有几个不同的现值，我们选择优先考虑家庭＆gt;学校....例如，西莉亚和凯特都在2012年收到礼物，但西莉亚在2012年获得了家居礼物和学校礼物，在这种情况下我们选择她的家庭现值来进行计算）并且外出应该是如下：

Name              ExactDate        PresentsDiff
celiaminuskate     2011                      3
celiaminuskate     2012                      6

到目前为止，我有：

SELECT 'celiaminuskate'AS [NAME],T1.[date] AS [EXACT DATE],
T1.presents T2.presents AS [PRESENTS DIFF]
FROM Some_Table T1, Some_Table T2

部分我认为需要修复？

WHERE (T1.Name = 'celia1'>'celia2')
AND (T2.Name = 'kate1'>'kate2')
AND T2.ExactDate = T1.ExactDate

表示优先顺序？我不太清楚该怎么做

ORDER BY T1.ExactDate

Answer 1

我创建了这个查询并将其保存为qryCeliaAndKateGiftDates。它只返回不同的ExactDate值，其中celia和kate都记录了礼物。

注意我将名称字段重命名为收件人，因为名称是保留字。

SELECT DISTINCT celia.ExactDate
FROM
    [SELECT ExactDate
    FROM Some_Table
    WHERE Recipient Like "celia*"
    ]. AS celia
    INNER JOIN [
        SELECT ExactDate
        FROM Some_Table
        WHERE Recipient Like "kate*"
        ]. AS kate
    ON celia.ExactDate = kate.ExactDate
ORDER BY celia.ExactDate;

然后我使用相关子查询在每个ExactDates上为celia和kate返回正确的Presents值。

SELECT
    raw.recipients AS [NAME],
    raw.ExactDate  AS [EXACT DATE],
    (raw.celia_presents - raw.kate_presents) AS [PRESENTS DIFF]
FROM
    [SELECT
    'celiaminuskate' AS recipients,
    dates.ExactDate,
    (SELECT TOP 1 Presents
    FROM Some_Table
    WHERE
        Recipient Like "celia*"
        And ExactDate = dates.ExactDate
    ORDER BY Location) AS celia_presents,
    (SELECT TOP 1 Presents
    FROM Some_Table
    WHERE
        Recipient Like "kate*"
        And ExactDate = dates.ExactDate
    ORDER BY Location) AS kate_presents
    FROM qryCeliaAndKateGiftDates AS dates]. AS raw;

它返回从Access 2003运行时请求的结果。但是相关的子查询非常慢，所以我很想知道你得到的其他答案。

使用EXTRA CRITERIA在两行之间进行计算？

1 个答案: