If you have an issue uploading a database in phpMyAdmin, such as error messages, there are usually 3 main reasons for this:
Database file size too large
If you are trying to upload a very large database, this can cause an error when uploading the file. The maximum upload size for a database on our servers is 256MB. If your database is larger than 256MB, you can try uploading the database via Backup under FIles in cPanel and use the Restore a MySQL Database Backup option. Please make sure the database file name is the same as the database you have created.
Incorrect file format
When importing a database on phpMyAdmin, please make sure that your file’s format is .sql. You can also import compressed files such as gzip, bzip2 and zip such as filename.sql.zip.
Corrupted database file
If you are using a file less than 256MB in size and have checked it is the correct format, any errors could indicate a corrupted database file.