Retrieving unique values from columns in one query

I have a table where I need display only unique values from each column. For example, take this table below. How can I retrieve only one record of 'A,B,C, or D' from col_1, one record of 'Y and N', and one record of 'Y and N' for col_3 ?

 my_table
 
 Col_1     Col_2   Col_3 
 
 A           Y       N
 B           N       Y
 C           Y       Y
 A           N       Y
 D           N       N
 B           Y       N

 
 Col_1     Col_2   Col_3 
 
 A           Y       Y
 B           N       N
 C                            
 D

You can't accomplish this in a single SQL statement. That is because SQL is designed to return a row as a distinct member of a result set. But in your output, you are asking for SQL to return each row as differing members of differing result sets. You'll need to accomplish this through PL/SQL or through your application programming language.

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