Ersin Acar

Sometimes, especially when moving data from one server to another, you might find that you have your MySQL database incorrectly encoded. Problem with this first show itself if you have the database and encoded in one charset set to display your website in another. If this is the case then you will find strange characters [...]

To find duplicate values you need to use the MySQL COUNT() function and then pick out all of the counts that are greater than one.

SELECT value,COUNT(value) AS Count
FROM test
GROUP BY value
HAVING (COUNT(value) > 1)
ORDER BY Count DESC;

Conversely you can also select the rows that only have a single entry.

Sometimes, especially when moving data from one server to another, you might find that you have encoded your MySQL database incorrectly. This problem with first show itself if you have the database encoded in one charset and your website set to display in another. If this is the case then you will find strange characters [...]