I googled a lot, but either I used the wrong keywords or there are no simple solutions on the internet. I hope somebody here can help me.
Best regards and thanks in advance.
After a hard work, i got the solution finally, There is two methods to do this:
Method 1: Create two domains and in each domain have the same name to the Date column.
Method 2: Create a join between the two derived tables, then you can add the two derived table to the Ad hoc editor, and finally put the same field (Date) in the row .... but this method is just to appear the Date in the Multiple Reports Controls and it may execute a wrong Query (join between to tables) to give a wrong data and finally to generate an Untrusted report !!! So be careful when you try to do this method !!! I suggest you to use the first method ...
Thanks @ernestoo for your efforts, I don't understand what you mean ! but i think that is the same idea between us !
You need to define the "Date" control outside of the report- what I mean is that there are two ways: define inside the report unit or outside of it in a folder, for example named "common" where you store the common controls