Why there is a need php?

Answer 1

you need any language to power up server ..... but you don't have much knowledge .....and don't mind a dying language ....
then you need PHP

Answer 2

backend/database managment.

Answer 3

unlike java, php does't need to compile, and can be done "on the go". it easily comunicates with databases, and is the most popular coding language for web sites

Answer 4

php does compile, it runs on a php driver and is translated to a c language.

php is needed as part of the Linux Apache MySql PHP stack. it's the primary http server language for Linux OS.