Cumulative Sum in Oracle

In this post, I am sharing the code to calculate Cumulative sum in Oracle

Table Sample Data

Query to get Cumulative Sum of Amount on the basis of Type

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SELECT NUM        , DECODE(TYPE, 'DR', AMOUNT)        , DECODE(TYPE, 'CR', AMOUNT)        , SUM (DECODE(TYPE, 'CR', AMOUNT, -1 * AMOUNT))          OVER (ORDER BY NUM ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW)          AS BALANCE FROM TBL GROUP BY NUM, TYPE, AMOUNT

Output