Aggregation in QlikView is usually done in the UI. There is a SUM() aggregation function that can be used in Text Boxes (to sum exeverything selected) or in an Excel Worksheet-like object like a Straight Table.
Internal tables can be viewed as Excel Worksheets. They contain rows and columns. Load your data as-is, and aggregate in the User Interfac, just like in Excel.
For example, if your field in the above example data is called... Example, load the data as-is and create a text box. In the expression field, type =Sum(Example).
If you want to aggregate in the Load script, you won't be able to un-aggregate again later on. To sum values in your load script, use the GROUP BY clause and again a Sum() function to sum column values from different rows.