oracle sql語句實現累加、累減、累乘、累除

在oracle開發過程當中常常會遇到累加、減、乘、除的問題。下面對這個作個小的總結

---建立測試表

CREATE TABLE TEST(
    PARENT_ID NUMBER,
    PART_ID NUMBER,
    QUALITY NUMBER);

INSERT INTO TEST VALUES(1,1,2);
INSERT INTO TEST VALUES(1,2,3);
INSERT INTO TEST VALUES(1,3,2);
INSERT INTO TEST VALUES(1,4,5);
INSERT INTO TEST VALUES(2,2,3);
INSERT INTO TEST VALUES(2,3,5);
INSERT INTO TEST VALUES(2,4,7);

1、實現累加

SELECT
    T.*,
    SUM(T.QUALITY) OVER (PARTITION BY T.PARENT_ID ORDER BY T.PART_ID) RUNNING_QUALITY
FROM
    TEST T

2、實現累減

SELECT
    T.PARENT_ID,
    T.PART_ID,
    T.QUALITY,
    SUM(DECODE(T.RN,1,T.QUALITY,-T.QUALITY)) OVER(PARTITION BY T.PARENT_ID ORDER BY T.PART_ID) RUNNING_PROD
FROM
    (
        SELECT
            T.*,
            ROW_NUMBER() OVER(PARTITION BY T.PARENT_ID ORDER BY T.PART_ID) RN
        FROM
            TEST T) T

3、實現累乘

SELECT
    T.*,
    ROUND(EXP(SUM(LN(T.QUALITY)) OVER(PARTITION BY T.PARENT_ID ORDER BY T.PART_ID)),0) RUNNING_PROD
FROM
    TEST T

4、實現累除

SELECT
    T.PARENT_ID,
    T.PART_ID,
    T.QUALITY,
    EXP(SUM(DECODE(RN,1,LN(T.QUALITY),-LN(T.QUALITY))) OVER(PARTITION BY T.PARENT_ID ORDER BY T.PART_ID)) RUNNING_PROD
FROM
    (
        SELECT
            T.*,
            ROW_NUMBER() OVER(PARTITION BY T.PARENT_ID ORDER BY T.PART_ID) RN
        FROM
            TEST T)T

累乘和累除的缺陷是不能對負數進行運算 由於ln(負數)沒有意義