How can I export just the structure of a MySQL database?
Since you specifically asked about phpMyAdmin and the previous answers, while correct, are both about doing this on the command line:

Navigate to the database you wish to export. Across the top row of tabs click "Export"



Next, click the Custom radio button



Halfway down the "Format-specific options" area, select "structure" (the default is "structure and data")


Check the other options and press Go to download your .sql file with no data, only the table structure.