在这种情况下如何高效地编写这个sql查询答案

【问题标题】：How to write this sql query efficiently in this case在这种情况下如何高效地编写这个sql查询
【发布时间】：2014-06-26 04:46:19
【问题描述】：

在这里，我有一个类似下面的查询，正在循环子 ID 并将其传递给该查询并获得适当的结果。这里我有 33 个子 ID，所以这个查询的结果包含 33 行

DECLARE @DATETIMENOW DATETIME  
SET @DATETIMENOW = GETDATE()-7 

SELECT COUNT(1) FROM  BKA.CHILDEVENTS CHE JOIN BKA.CHILDEVENTPROPERITIES CHEP ON CHEP.EVENTID = CHE.EVENTID  
                      WHERE (CHE.TYPE = 'ACCIDENT' OR (CHE.TYPE = 'BREAK' AND CHEP.PROPERTY = 'SUCCESS' AND CHEP.PROPERTYVALUE = 'FALSE'))  
                      AND CHE.CHILDID = @CHILDID AND CHE.ADDDATE BETWEEN DATEADD(DD, -(DATEPART(DW, @DATETIMENOW-7)-1), @DATETIMENOW-7) AND  
                      DATEADD(DD, 7-(DATEPART(DW, @DATETIMENOW-7)), @DATETIMENOW-7) AS PREVIOUSWEEKACCIDENTS

在这里，我尝试在此查询中使用 join 而不是循环 childid，但在一行中得到结果。我在这做错了什么

DECLARE @DATETIMENOW DATETIME  
SET @DATETIMENOW = GETDATE()-7 
SELECT COUNT(1) FROM  BKA.CHILDEVENTS CHE JOIN BKA.CHILDEVENTPROPERITIES CHEP 
                      ON CHEP.EVENTID = CHE.EVENTID 
                      JOIN  BKA.CHILDINFORMATION CHINFO
                      ON CHE.CHILDID = CHINFO.CHILDID
                      WHERE (CHE.TYPE = 'ACCIDENT' OR (CHE.TYPE = 'BREAK' AND CHEP.PROPERTY = 'SUCCESS' AND CHEP.PROPERTYVALUE = 'FALSE'))  
                      AND CHE.ADDDATE 
                      BETWEEN DATEADD(DD, -(DATEPART(DW, @DATETIMENOW-7)-1), @DATETIMENOW-7) AND  
                      DATEADD(DD, 7-(DATEPART(DW, @DATETIMENOW-7)), @DATETIMENOW-7)

有什么建议吗？

【问题讨论】：

标签： sql-server-2008 tsql join

【解决方案1】：

您需要添加一个 GROUP BY 子句：

SELECT  CHINFO.CHILDID
      , COUNT(1)
FROM    BKA.CHILDEVENTS CHE
        JOIN BKA.CHILDEVENTPROPERITIES CHEP ON CHEP.EVENTID = CHE.EVENTID
        JOIN BKA.CHILDINFORMATION CHINFO ON CHE.CHILDID = CHINFO.CHILDID
WHERE   ( CHE.TYPE = 'ACCIDENT'
          OR ( CHE.TYPE = 'BREAK'
               AND CHEP.PROPERTY = 'SUCCESS'
               AND CHEP.PROPERTYVALUE = 'FALSE'
             )
        )
        AND CHE.ADDDATE BETWEEN DATEADD(DD,
                                        -( DATEPART(DW, @DATETIMENOW - 7) - 1 ),
                                        @DATETIMENOW - 7)
                        AND     DATEADD(DD,
                                        7 - ( DATEPART(DW, @DATETIMENOW - 7) ),
                                        @DATETIMENOW - 7)
GROUP BY CHINFO.CHILDID

【讨论】：

但不显示空值..我尝试了左外连接，但仍然没有得到结果中的空值
在哪里将左连接更改为连接

【解决方案2】：

where 中的值将使外连接无效

SELECT CHE.CHILDID
     , COUNT(1)
  FROM BKA.CHILDEVENTS CHE
  LEFT JOIN BKA.CHILDEVENTPROPERITIES CHEP 
    ON CHEP.EVENTID = CHE.EVENTID
   AND ( CHE.TYPE = 'ACCIDENT'
          OR ( CHE.TYPE = 'BREAK'
               AND CHEP.PROPERTY = 'SUCCESS'
               AND CHEP.PROPERTYVALUE = 'FALSE'
             )
       )
   AND CHE.ADDDATE BETWEEN DATEADD(DD,
                                        -( DATEPART(DW, @DATETIMENOW - 7) - 1 ),
                                        @DATETIMENOW - 7)
                       AND DATEADD(DD,
                                        7 - ( DATEPART(DW, @DATETIMENOW - 7) ),
                                        @DATETIMENOW - 7)    
GROUP BY CHE.CHILDID

【讨论】：

+1 给 Suart，因为我使用了他的 TSQL。这个问题在评论中有一个小时，所以我继续回答。

【解决方案3】：

          DECLARE @DATETIMENOW DATETIME  
          SET @DATETIMENOW = GETDATE()

              SELECT  B.WEEK FROM BKA.CHILDINFORMATION CI LEFT OUTER JOIN 

              (SELECT Distinct CHINFO.CHILDID,COUNT(*)  as week FROM  BKA.CHILDINFORMATION CHINFO               
               JOIN  BKA.CHILDEVENTS CHE 
                            ON CHE.CHILDID = CHINFO.CHILDID                                                       
               JOIN BKA.CHILDEVENTPROPERITIES CHEP 
                            ON  CHE.EVENTID = CHEP.EVENTID                         
              WHERE 
                          (CHE.TYPE = 'ACCIDENT' OR (CHE.TYPE = 'POTTYBREAK' AND CHEP.PROPERTY = 'SUCCESS' 
                          AND CHEP.PROPERTYVALUE = 'FALSE'))  
                            AND 
                            CHE.ADDDATE 
                            BETWEEN DATEADD(DD, -(DATEPART(DW, @DATETIMENOW-14)-1), @DATETIMENOW-14) AND  
                            DATEADD(DD, 7-(DATEPART(DW, @DATETIMENOW-14)), @DATETIMENOW-14)      group by CHINFO.CHILDID) b
                            on CI.ChildID = b.ChildID

【讨论】：