Question

我希望以下代码与多个结束日期一起运行。这些结束日期必须是该月的第一天。我可以在更改结束日期的同时多次执行代码，但这对于我需要从2001年到现在的montly数据的大量工作。所以我的猜测是我必须循环这个？

以下是我正在使用的代码：

Select t4.Count, t4.Status
From(
    SELECT count(l.VoerID) as Count, l.Datum, l.Status, l.LogID
      FROM (
             SELECT k.VoerID, k.Datum, MAX(k.LogID) AS LogID
               FROM DB.LogStatus k
                Where Datum > '2001-01-01'
                and Datum < '2013-07-01'
              GROUP BY k.VoerID
           ) m
      JOIN DB.LogStatus l
        ON l.VoerID = m.VoertuigID AND l.LogID = m.LogID
    Where status in ('x',y,'z')
    Group by Status
)t4

谁可以提供帮助？

编辑::::: @STEPH

当我使用这段代码的和平时（1）：

SELECT VoertID,max(LogID) as MaxLogID,Datum
          from DB.LogStatus
WHERE Datum >= '2001-01-01'
                    and Datum < '2013-07-01'
and VoerID = '50789'
GROUP BY VoerID

我使用最后一个LogID但不是相应的日期获得VoerID 50789。怎么可能？

Answer 1

根据您的输出，您需要操纵您的日期以始终返回本月的第一天。

在下面的SQL中，我提出了一个这样做的方法，它涉及计算在本月初（相对于每个日期）已经过去多少天并且减去它。

    SELECT date_sub(Datum,interval day(Datum)-1 day) datum, status, count(l.VoerID) as count
    FROM DB.LogStatus l
INNER JOIN (SELECT VoerID,max(LogID) as MaxLogID 
          from DB.LogStatus
WHERE Datum >= '2001-01-01'
                    and Datum < '2013-07-01'
GROUP BY VoerID) maxl on l.VoerID=Maxl.VoerID and l.LogID=Maxl.MaxLogID

Where status in ('x','y','z')
and Datum >= '2001-01-01'
                and Datum < '2013-07-01'

GROUP BY date_sub(Datum,interval day(Datum)-1 day),status

分解原始代码：

返回给定的VoerID，返回FIRST Date和MAX LogID

       SELECT k.VoerID, k.Datum, MAX(k.LogID) AS LogID 
       FROM DB.LogStatus k

       Where Datum > '2001-01-01'

       and Datum < '2013-07-01'

      GROUP BY k.VoerID

从日志中获取状态在一定范围内且LogID匹配的所有项目，表格中的VoerID与派生表中的VoertuigID匹配（实际上不存在于代码中）。按日志状态分组并获取FIRST Datum，FIRST LogID和COUNT

      SELECT count(l.VoerID) as Count, l.Datum, l.Status, l.LogID
            FROM (            step1           ) m
            JOIN DB.LogStatus l
              ON l.VoerID = m.VoertuigID AND l.LogID = m.LogID
          Where status in ('x',y,'z')
          Group by Status

从2

修订后的代码确实：

标识特定日期内每个VoerID的最后一个LogID

 SELECT VoerID,max(LogID) as MaxLogID 
          from DB.LogStatus
WHERE Datum >= '2001-01-01'
                    and Datum < '2013-07-01'
GROUP BY VoerID

通过这些最大LogID限制日志，然后过滤相关状态，然后计算每个月的每个状态的行数

SELECT date_sub(Datum,interval day(Datum)-1 day) datum, status, count(l.VoerID) as count

FROM DB.LogStatus l
INNER JOIN ( m  ) maxl on l.VoerID=Maxl.VoerID and l.LogID=Maxl.MaxLogID
Where status in ('x','y','z')
and Datum >= '2001-01-01'
and Datum < '2013-07-01'
GROUP BY date_sub(Datum,interval day(Datum)-1 day),status

MYSQL循环此代码

1 个答案: