我也不确定为什么没有按PARTITION BY Y.ACCT_DIM_NB，Y.DAY_TIME_DIM_NB或ORDER BY
Y.DAY_TIME_DIM_NB，Y.TXN_POSTING_SEQ对分区进行分区

不知道，但这会返回不同的结果（并且Y.DAY_TIME_DIM_NB不需要，ORDER BY因为它已经被它分区了）

另外，仅在整个分区窗口中，行数在未绑定的前导和当前行之间行吗？

与完全相同ROWS UNBOUNDED PRECEDING，即“累积最大值”的语法变体。分区是ROWS UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING

RESET WHEN在Teradata中做什么？

这RESET WHEN是用于动态添加分区的Teradata扩展，它是两个（在您的情况下）或三个嵌套的OLAP函数的较短语法：

-- using RESET WHEN
MAX(A.RUN_BAL_AM)
OVER (PARTITION BY A.ACCT_DIM_NB
      ORDER BY A.DAY_TIME_DIM_NB, A.TXN_POSTING_SEQ 
      RESET WHEN A.CS_TXN_CD NOT IN ('072','075','079','107','111','112','139','181','318') 
      ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS  EOD_BAL_AM



-- Same result using Standard SQL
SELECT  
   Max(A.RUN_BAL_AM)
   Over (PARTITION BY A.ACCT_DIM_NB, dynamic_partition
         ORDER BY A.DAY_TIME_DIM_NB, A.TXN_POSTING_SEQ 
         ROWS BETWEEN Unbounded Preceding AND CURRENT ROW) AS  EOD_BAL_AM

FROM 
 ( 
   SELECT
      -- this cumulative sum over 0/1 assigns a new value for each series of rows based on the CASE
      Sum(CASE WHEN A.CS_TXN_CD NOT IN ('072','075','079','107','111','112','139','181','318') THEN 1 ELSE 0 end)
      Over (PARTITION BY A.ACCT_DIM_NB, dynamic_partition
            ORDER BY A.DAY_TIME_DIM_NB, A.TXN_POSTING_SEQ 
            ROWS Unbounded Preceding) AS dynamic_partition
   FROM ...
 ) AS dt