Question

早上好;

我有下表

Date       Duration         COT             TD            RID
6/26       30               PT              OT            1
6/26       15               OT              PT            1
6/27       60               PT              OT            1
6/27       60               OT              PT            1
6/28       15               SS              MM            1
6/28       30               SS              MM            1
6/28       15               MM              SS            1
6/28       30               MM              SS            1

我想要做的是通过加入表格来记录以下内容：

T1.TD = T2.COT
T1.COT = T2.TD
T1.Duration＆lt;＆gt; T2.Duration
T1.Date = T2.Date
T1.RID = T2.RID

T1和T2是同一张表。到目前为止我所拥有的是：

SELECT *
FROM T1
WHERE NOT EXISTS (SELECT 1 FROM T2
    WHERE T1.Date = T2.Date 
    AND T1.COT = T2.TD 
    AND T1.TD = T2.COT
    AND T1.RID = T2.RID 
    AND T1.Duration = T2.Duration)

显然上面有两行，因为2行符合这个标准。但是，我真的只想从表中获得一行。有没有办法做到这一点，或者可能以不同的方式去做呢？

编辑：添加了其他行 - 不应选择任何行。即使在6/28上存在不匹配的行，它们也会匹配 - 第1行和第3行，第2行和第4行匹配6/28，因此应该限制在最终数据集中。换句话说，如果RID的某一天有任何匹配记录，则不要选择它们。

Answer 1

你快到了。只需使用AS关键字将表别名为两个不同的名称，然后使用您在问题中提出的标准，如下所示。

Select * from Table as T1 
Join Table as T2 on T1.TD = T2.COT 
AND T1.COT= T2.TD
AND T1.Duration <> T2.Duration
AND T1.Date = T2.Date
AND T1.RID = T2.RID
WHERE T1.Duration < T2.Duration

Here are the results!

<强> UDPATE

根据您的新标准，您正在寻找SO19249978是您的表名称。生成Remove表的子查询选择您不想要的行，然后我们join将它们添加到结果中。我们正在寻找连接值为null的行，就像连接匹配时我们需要删除行。

Select T1.Date, T1.Duration as minDur, T2.Duration as maxDur, T1.COT, T1.TD, T1.RID
from SO19249978 as T1 
Join SO19249978 as T2 on T1.TD = T2.COT 
AND T1.COT= T2.TD
AND T1.Duration <> T2.Duration
AND T1.Date = T2.Date
AND T1.RID = T2.RID
LEFT JOIN (
    Select Date, Duration, RID 
    from SO19249978
    GROUP BY Date, Duration, RID
    Having Count(*) > 1
     ) as Remove ON T1.Duration=Remove.Duration
          AND T1.Date= Remove.Date 
          AND t1.RID = Remove.RID
WHERE Remove.Date is null

Answer 2

您可能需要在最终输出中设置您喜欢哪一行的标准。以下是一些例子：

如果在最终输出中需要任何随机行：

Select top 1 * from t1 as T1 
Join t1 as T2 on T1.TD = T2.COT 
AND T1.COT= T2.TD
AND T1.Duration <> T2.Duration
AND T1.Date1 = T2.Date1
AND T1.RID = T2.RID

如果您选择根据持续时间获取行：

Select * from t1 as T1 
Join t1 as T2 on T1.TD = T2.COT 
AND T1.COT= T2.TD 
AND T1.Duration <> T2.Duration 
AND T1.Date1 = T2.Date1
AND T1.RID 2.RID   
AND T1.duration > T2.duration

Answer 3

两点：

您必须使用任意条件来过滤双打
您应该将分组和加入的概念分开

尝试以下解决方案：

    SELECT 
      T1.TD, T1.COT, T1.DATE, T1.RID, MIN(T1.DURATION), MAX(T1.DURATION)
    FROM
       DEMO T1 JOIN DEMO T2 ON (
         T1.TD = T2.COT AND
         T1.COT = T2.TD AND
         T1.TD < T2.TD -- Arbitrary filtering one of each double
       )
    GROUP BY
       T1.TD, T1.COT, T1.DATE, T1.RID   
    HAVING
       MIN(T1.DURATION) <> MAX(T1.DURATION)
    ;

请在此处查看fiddle。

从具有多个比较的表中获取单个结果

3 个答案: