總和甲骨文窗函數

Question

誰能告訴我什麼是sum在Oracle分區sum(SUM(SUM(VAL)))裏面的意義，下面的代碼片段

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

其計算VAL總和每NMS（用於第一個）和EMPNO（第二個）。

先通過+ SUM（VAL）評估該組，然後分析計算該結果。

例如如果你有結果後組由

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

你必須SUM(SUM(VAL)) OVER(PARTITION BY NMS)作爲

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) 

你必須SUM(SUM(VAL)) OVER(PARTITION BY EMPNO)爲

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)