Select distinct column 1, column 2 from table name ; and select column 1, column 2 from tablename;

Question

what's the difference in between both the query .

Answer 1

In the first case, results will be filtered for unique column1 and column2 values from the table. whereas the later one, will result all the values from the table. we can have duplicates in the later one.

Answer 2

Of column one would always be distinct if it was the primary key