总和甲骨文窗函数

Question

谁能告诉我什么是sum在Oracle分区sum(SUM(SUM(VAL)))里面的意义，下面的代码片段

SELECT NMS, 
     SUM(SUM(VAL)) OVER(PARTITION BY NMS), ---- SIGNIFICANCE 
     EMPNO, 
     SUM(SUM(VAL)) OVER(PARTITION BY EMPNO) ---- SIGNIFICANCE 
    FROM PART_TEST_PART 
GROUP BY NMS, EMPNO; 

Answer 1

其计算VAL总和每NMS（用于第一个）和EMPNO（第二个）。

先通过+ SUM（VAL）评估该组，然后分析计算该结果。

例如如果你有结果后组由

EMPNO NMS SUM(VAL) 
1  a 15 
1  b 24 
2  a 50 

你必须SUM(SUM(VAL)) OVER(PARTITION BY NMS)作为

EMPNO NMS SUM(VAL) SUM(SUM(VAL)) OVER(PARTITION BY NMS) 
1  a 15  65 (15+50 for NMS = a) 
1  b 24  24 (24 for NMS = b) 
2  a 50  65 (15+50 for NMS = a) 

你必须SUM(SUM(VAL)) OVER(PARTITION BY EMPNO)为

EMPNO NMS SUM(VAL) SUM(SUM(VAL)) OVER(PARTITION BY EMPNO) 
1  a 15  39 (15+24 for EMPNO = 1) 
1  b 24  39 (15+24 for EMPNO = 1) 
2  a 50  50 (50 for EMPNO = 2)