oracle sql语句实现累加、累减、累乘、累除

在oracle开发过程当中常常会遇到累加、减、乘、除的问题。下面对这个作个小的总结

---建立测试表

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、实现累加

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

2、实现累减

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、实现累乘

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、实现累除

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对负数进行运算 由于ln(负数)没有意义