database - How to select unique records by SQL

Question

When I perform SELECT * FROM table I got results like below:

1 item1 data1
2 item1 data2
3 item2 data3
4 item3 data4

As you can see, there are dup records from column2 (item1 are dupped). So how could I just get result like this:

1 item1 data1
2 item2 data3
3 item3 data4

Only one record are returned from the duplicate, along with the rest of the unique records.

Answer 1

With the distinct keyword with single and multiple column names, you get distinct records:

SELECT DISTINCT column 1, column 2, ...
FROM table_name;