It should be done via terminal as below.
- In the terminal navigate to bin folder of MAMP using below command cd /Applications/MAMP/library/bin
- Use this command to export the file ./mysqldump -u [USERNAME] -p [DATA_BASENAME] > [PATH_TO_FILE]. EG would be ./mysqldump -u root -p my_database_name > /Applications/MAMP/htdocs/folder_name/exported_db.sql
- Line should appear saying Enter password:. Here enter the MySQL password. keep in mind that the letters will not appear, but they are there. If you need to import use BigDump Which is a MySQL Dump Importer.
Credit : Stackoverflow