Thanks very much for your prompt response. I have followed the instruction mentioned in the thread you shared, the result wasn't what I want.
1. The thread seems to show how to display the last value at each period end, RATHER THAN accumulating the transactional amounts from day 1 through target date as the closing balances
2. The method adopted by the thread can only display the calculated figures on each new row, INSTEAD OF new columns in the crosstab.
Therefore the methods mentioned in the thread seem irrelevant to my problem.
Could you suggest other references? Actually I have already spent some time in googling / youtube / Tableau KB etc. but no irrelevant reference could be found. Perhaps I had used the wrong key words to describe my problem.
Sorry for any confusion and thanks again.