Oracle Window Functions Execution Process
The general flow of execution for Oracle window functions is as follows:
- First, identify the dataset to which the window function is applied, including determining the sorting order and partitioning of the dataset.
- Next, the data set is grouped according to the partition method of the window function.
- Sort the data within each group according to the ordering rules of the window function.
- Apply window functions to the data within each group to calculate the result of the window function.
- Finally, return the results of the window function within each group to the user.
Generally speaking, the execution process of window functions can be summarized simply as: grouping, sorting, applying window functions, and returning results.