How to remove duplicated data <p>I've got a database my_table <code>[id,first,second,third]</code> with a lot of entries and want to delete duplicate data of entries <code>[first,second,third]</code>.</p> <p>so that no duplicate for <code>first</code> and no duplicate for <code>second</code> and no duplicate for <code>third</code> just any duplicate on each then will be deleted.</p> <pre><code>id first second third 1 addy any robert 2 addy kevin steve 3 jack ben adam </code></pre> <p>here i will remove duplicate for <code>first</code> so remove <code>2 addy kevin steve</code></p>