what is an SEO ?

Seo stands for search engine optimisation ,it is basically study of search engine,in which we learn how to rank our web pages higher in search engines .offlate seo has gained popularity among web marketers as it is the free way of promoting our websites.

what is MySql ?

MySql is the open source/relational database management system ,it is based of structured query language .It is very fast and reliable database server ,this is often used with php .There are plenty of uses of Mysql server .