联接时无法绑定多部分标识符

Question

无法弄清楚为什么我不能执行此连接，过去我做了很多类似的事情。我想念什么吗？

SELECT *
FROM THB_View.PCM_PCM_BASE base
LEFT OUTER JOIN THB_View.PCM_PCM_BASE_REOCCUR rec
LEFT OUTER JOIN THB_View.ATV atv ON base.PCM_TAG = atv.ATV_OCCURRING_PCM_TAG
     ON base.RECORD_KEY = rec.RECORD_KEY
WHERE
    base.PCM_STATUS = 'ENROUTE'
    AND rec.PCM_HRC_TAG IS NULL OR rec.PCM_HRC_TAG = ''
    AND rec.PCM_EQP_TAG IS NULL OR rec.PCM_EQP_TAG = ''

错误发生在SQL语句的第5行base.PCM_TAG

Answer 1

您的from子句不是编写join的典型方法。这是允许的，但这会影响标识符的范围。本质上，这被解释为：

from THB_View.PCM_PCM_BASE base left join
     (THB_View.PCM_PCM_BASE_REOCCUR rec left join
      THB_View.ATV atv
      on base.PCM_TAG = atv.ATV_OCCURRING_PCM_TAG
     )
     on base.RECORD_KEY = rec.RECORD_KEY

其中解释了为什么无法识别base。

只需在对表join进行编辑之后，以on条件编写join的标准方法：

from THB_View.PCM_PCM_BASE base left join
     THB_View.PCM_PCM_BASE_REOCCUR rec 
     on base.RECORD_KEY = rec.RECORD_KEY left join
     THB_View.ATV atv
     on base.PCM_TAG = atv.ATV_OCCURRING_PCM_TAG