Using PHP mysqli_query to Execute MySQL Queries

MySQL is a widely used relational database management system, and when developing web applications PHP offers several functions to connect to and operate MySQL databases. The mysqli_query function is one of the most common ways to execute queries.

mysqli_query can run various types of SQL statements, including SELECT , INSERT , UPDATE , and DELETE . It takes two parameters: the database connection object and the SQL query string. The following example demonstrates a SELECT query.

';
}

// 释放结果集
mysqli_free_result($result);

// 关闭数据库连接
mysqli_close($connection);
?>

The code first creates a database connection and checks for success. It then uses mysqli_query to execute a SELECT statement, stores the result in $result , and iterates over the rows with mysqli_fetch_assoc to print each record's ID, name, and age. Finally, it frees the result set and closes the connection.

Beyond SELECT , the same function can execute other statements such as INSERT , UPDATE , and DELETE by passing the appropriate SQL as the second argument.

When mysqli_query runs a SELECT , it returns a result set object. You can retrieve rows using functions like mysqli_fetch_assoc , mysqli_fetch_row , or mysqli_fetch_array , depending on the desired format.

In summary, the PHP mysqli_query function provides a convenient and efficient way to interact with MySQL databases for a variety of CRUD operations.