If you have a table and want to swap two field values together, here is a simple snippet.
If you have a mysql table and want to retrieve which are duplicated for one or more rows, here is how to do this : 1) You have to group results by the column(s) itself 2) Select the column(s) and its count as well 3) Use having to only get those that their count is greater than 1
If you want to get a table column names from mysql database as a concatenated string, you can use the following code