Perspective approach:
1. Insert -- PivotTable, a "Create PivotTable" window will pop up, click OK.
2. Select the required fields to create, as shown in the figure:
3. Drag the value to be summed from the position of "row" to the position of "value", and set it as summation
4. If the source table is set as a problem, all values will be displayed as 0 when summing, and the format of the source table can be set to normal
