Distinct not working as expected with sql

Question

How does distinct work with the following table:

id  | id2    | time
-------------------
1   | 5555 | 12
2   | 5555 | 12
3   | 5555 | 33
4   | 9999 | 44
5   | 9999 | 44
6   | 5555 | 33

select distinct * from table

Answer 1

If you use select distinct * from table all the row are distinct

if you use

 select distinct id2  , time from table

then you obtain

    id2 | time

   5555 | 12
   5555 | 33
   9999 | 44

With distinct you obtain the distinct rows based on the result of the select

Answer 2

此处的每一行都是不同的，因此distinct将没有可见的效果，并且所有行都将被返回。

Answer 3

Select Distinct ID2 From SomeTable

将返回5555 9999