There is no single command that looks into a list of tables.

You will have to build such a data access.

The most straightforward way would be to write a SQL statement that is fixed for the data you are looking for. Since this is not particularly useful for the next EBELN/EBELP values, a more dynamic approach would involve using SQL Script and variables. In case you are using a host programming language (JAVA, C, ABAP), you can put this variable simply into a prepared statement and get the same result without SQLScript.

A simple example:

create column table x1 as (select user_name from users );
create column table x2 as (select user_name from users );
create column table x3 as (select user_name from users );

insert into x2 values ('LARS');
insert into x3 values ('LARS');

do begin
declare search_name nvarchar(256) ='LARS';

              select 'x1' as src, count(*) cnt from x1 where user_name = :search_name
    union all select 'x2' as src, count(*) cnt from x2 where user_name = :search_name
    union all select 'x3' as src, count(*) cnt from x3 where user_name = :search_name;
end;

From here you should be able to extend to your use case and output preferences.

As a recommendation, I like to add that you should not try to make the solution to this overly dynamic. Typing this in for twenty tables is done very quickly and results in a simple to maintain setup. Throwing in cursors and loops or more complicated dynamic programming approaches will likely take a lot more time and "bite" you later when trying to maintain the solution.