Add "info about mysqli" (#18720)

* Add "info about mysqli"

Add the section "Some Important MYSQLi functions and their uses"
Add the link "for more information"

* Update index.md

client/src/pages/guide/english/php/working-with-databases/mysqli/index.md

@@ -8,6 +8,19 @@ This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/
 <a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
 
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+MYSQLi functions allow access to the database.
+MYSQLi is an improved version of MYSQL
+
+#### Some Important MYSQLi functions and their uses:
+mysqli_connect() ==> Opens a new connection to the MySQL server
+mysqli_query() ==> Performs a query against the database
+mysqli_error() ==> Returns the last error description for the most recent function call
+mysqli_close() ==> Closes a previously opened database connection
+mysqli_connect_error() ==> Returns the error description from the last connection error
+mysqli_select_db() ==> Changes the default database for the connection
+mysqli_fetch_assoc() ==> Fetches a result row as an associative array
+
 
 #### More Information:
 <!-- Please add any articles you think might be helpful to read before writing the article -->
+<a href="https://www.w3schools.com/php/php_ref_mysqli.asp">Click here</a> For more information about MYSQLi