Html page structure
<!DOCTYPE html>
        This is the Page Title
      <h3>Heading Sample</h3>
      <p>Sample paragraph</p>
PHP tags
When PHP parses a file, it looks for opening and closing tags, 
which are <?php and ?> which tell PHP to start and stop interpreting the code between them.
If a file contains only PHP code, it is preferable to omit the PHP closing tag at the end of the file.
Mysql connecting and disconnecting
Connecting and Disconnecting from the server
shell&gt; mysql -h host -u user -p
Enter password: ********
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 12345 to server version: 8.0.20-standard
Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

mysql> QUIT