How to find duplicated values in MySQL (or/and probably any other RDBM)

As an example I take one real (almost) table I have in my db. Structure is very simple : Table name: “words”, field “filename” name of the file and “words” just some information about each file. +—————–+———————+ | filename | words | +—————–+———————+ Suddenly we had a few files with exactly same name and […]