Answer by Rahul K Jha for MySQL 5.5 Update to MySQL 5.7

You can see my comment that the solution by @Rinzwind did not worked in my case (Ubuntu 14.04 , Mysql 5.5).So i have googled the solution and found the answer which worked for me at Digital Ocean Tutorial.

First of all , Backup All your Database.

mysqldump --all-databases > all_databases.sql

If above command did not work for you try below one.

mysqldump -u root -p --all-databases > all_databases.sql

I am pasting the particular portion of tutorial that worked for me .

If you want to install MySQL 5.7, you'll need to add the newer APT package repository from the MySQL APT repository page. Click Download on the bottom right, then copy the link on the next page from No thanks, just start my download. Download the .deb package to your server.

wget https://dev.mysql.com/get/mysql-apt-config_0.8.1-1_all.deb

Next, install it using dpkg.

sudo dpkg -i mysql-apt-config_0.8.1-1_all.deb

You'll see a prompt that asks you which MySQL product you want to configure. The MySQL Server option, which is highlighted, should say mysql-5.7. If it doesn't, press ENTER, then scroll down to mysql-5.7 using the arrow keys, and press ENTER again.

Once the option says mysql-5.7, scroll down on the main menu to Apply and press ENTER again. Now, update your package index.

sudo apt-get update

Finally, install the MySQL-server package, which now contains MySQL 5.7.

sudo apt-get install mysql-server

Now upgrade all mysql databases .

sudo mysql_upgrade -u root -p

Now restart mysql server .

sudo service mysql restart

Always find the latest version of mysql-at-config file at https://dev.mysql.com/downloads/repo/apt/