Question

Explain MySQLi Queries with examples.

Answer 1

• Performing Queries:

The main goal of MySQL and PHP connectivity is to retrieve and manipulate the data from MySQL database server. The SQL query statements are helping with PHP MySQL extension ^to achieve the objective of MySQL and PHP connection. “mysqli_query” is a function, helps to execute the SQL query statements in PHP scripting language.

Syntax:

mysqli_query(“Connection Object” “SQL Query”)

Example:

$con=mysqli_connect(“localhost”,“my_user”,“my_password”,“Student_DB”); $sql=“SELECT student_name,student_age FROM student”;mysqli_query($con,$sql);

• Closing Connection:

mysqli_close( ) Function is used to close an existing opened database connection between. PHP scripting and MySQL Database Server.

Syntax:

mysqli_close(“Connection Object”);

<?php
$con=mysqli_connect(“localhost”,“$user”,“$password”,“SCHOOLDB”);
// ….some PHP code… mysqli_close($con);
?>

Example of PHP and MySQL Program:

<?php .
$servemame = “localhost”;
$usemame = “username”;
$password = “password”;
$dbname = “schoolDB”;
$connection = mysqli_connect(“$servemame”, “$usemame”, “$password” “$dbname”);
if (mysqli_connect_error ( ))
{
echo “Failed to connect to MySQL:”
mysqli_connect_error( );
}
sql stmt = “SELECT * FROM mycontacts”; //SQL select query
$result = mysqli_query($connection,$sql_stmt);//execute SQL statement$rows =
mysqli__num_r°ws($result);// get number of rows returned
if($rows) {
while ($row = mysqli_fetch_array($result)) {
echo ‘ID:’. $row[‘id’]. ‘<br>’;