The following is the tutorial to export and import your MySQL Database in gzip extension.
Your SQL Backup file is compressed using Gzip tool so to make its size smaller (From .sql to be .gz).
And then to perform either importing or restoring your file, your database archive will be firstly extracted using gunzip. The following is the command.
How to exporst MySQL databse to gzip
mysqldump -u user_name -p database_name | gzip -9 > database_name.sql.gz
-9 : is the gzip compressing level (1-9).
How to import MySQL database from gzip
gunzip < database_name.sql.gz | mysql -u user_name -p database_name