连接:如何返回左外连接的空右侧的默认值

Question

在我的Oracle数据库中,我有一个左外连接,用于父工作订单到其子工作程序.然后我运行一个计算执行一些子值的SUM().我将来自Nvl()中的子工作程序的结果包装起来,以确保它们能够正确计算.

这是有效的,除非父母没有子工作人员.在这种情况下,显示期间返回的"空值"是因为连接中没有结果,因此看起来Nvl([fieldname],0)不会将它们转换为显示0.因此,当我认为总结时具有父值的子值,由于向空值添加值,它们也返回null.

什么是最好的解决方法？这是可以解决的问题,还是从根本上解决了我的查询有问题的气味？

查询

对不起,我暂时无法发布设置.对于此特定工作顺序(硬编码),连接的"右手"部分为空,因为父级没有子级,因此显示为null.

SELECT *
FROM   (SELECT *
        FROM   R_PCR_ALLWOSANDTASKSSEPARATELY)WOINFO
       LEFT OUTER JOIN (SELECT WORKORDERNUMBER                AS TASKWORKORDRENUMBER
                               , PARENT                       AS TASKPARENT
                               , NVL(TOTALMATESTCOSTFORWO, 0) AS TOTALMATESTCOSTFORWO_TASK
                               , NVL(TOTALLABESTCOSTFORWO,0)         AS TOTALLABESTCOSTFORWO_TASK
                               , NVL(TOTALMATACTCOSTFORWO,0)         AS TOTALMATACTCOSTFORWO_TASK
                               , NVL(TOTALLABACTCOSTFORWO,0)         AS TOTALLABACTCOSTFORWO_TASK
                               , NVL(TOTALLABACTHOURSFORWO,0)        AS TOTALLABACTHOURSFORWO_TASK
                        FROM   R_PCR_ALLWOSANDTASKSSEPARATELY)TASKINFO
         ON ( WOINFO.WORKORDERNUMBER = TASKINFO.TASKPARENT )
WHERE  WORKORDERNUMBER = '2826059'; 

Answer 1

在LEFT join返回结果后,您需要应用NVL.

试试这个:

SELECT  WOINFO.*
                , TASKWORKORDRENUMBER
                , TASKPARENT
                , NVL(TOTALMATESTCOSTFORWO_TASK,0) AS TOTALMATESTCOSTFORWO_TASK
                , NVL(TOTALLABESTCOSTFORWO_TASK,0) AS TOTALLABESTCOSTFORWO_TASK
                , NVL(TOTALMATACTCOSTFORWO_TASK,0) AS TOTALMATACTCOSTFORWO_TASK
                , NVL(TOTALLABACTCOSTFORWO_TASK,0) AS TOTALLABACTCOSTFORWO_TASK
                , NVL(TOTALLABACTHOURSFORWO_TASK,0) AS TOTALLABACTHOURSFORWO_TASK
FROM   R_PCR_ALLWOSANDTASKSSEPARATELY WOINFO
       LEFT OUTER JOIN (SELECT WORKORDERNUMBER                AS TASKWORKORDRENUMBER
                               , PARENT                       AS TASKPARENT
                               , TOTALMATESTCOSTFORWO_TASK
                               , TOTALLABESTCOSTFORWO_TASK
                               , TOTALMATACTCOSTFORWO_TASK
                               , TOTALLABACTCOSTFORWO_TASK
                               , TOTALLABACTHOURSFORWO_TASK
                        FROM   R_PCR_ALLWOSANDTASKSSEPARATELY) TASKINFO
         ON ( WOINFO.WORKORDERNUMBER = TASKINFO.TASKPARENT )
WHERE  WORKORDERNUMBER = '2826059';