HANA select CURRENT_DATE output empty cell

Question

I have a very simple problem with HANA SQL but I really can't understand the solution. My target is to output the current date.

If I write the following query in HANA Studio, it output an empty cell

SELECT current_date "current date" FROM DUMMY;

while if I write the following, it gives the current_date as output.

SELECT DISTINCT calendar_date "current date"
from CALTABLE
where calendar_date=current_date;

Why the first and the second query give different results?