mysql – need explain for group by behavior

Can someone to explain below group by result

I have a simple table “TableA” like this

ID --- Name (1  --- A_1) (2  --- A_2) (3  --- B_3) 

+when I run below group by

select Name from TableA group by Name 

— result will be

Name A_1 B_3 

Looklike it exclude Name=A_2 in my result

+when I applied below group by + count

select Name,count(1) cnt from TableA group by Name 

— result

Name --- cnt A1   --- 1 **A2   --- 1** B3   --- 1 

It show all rows as expected

I can use distinct to have a correct result for case 1 but still have concern why mysql have that behavior?

Thanks,