How to randomly obtain non-duplicate databases in php

In web development, PHP, as a popular server-side language, is often used to handle database-related operations. Among them, randomly extracting non-duplicate data is an important part. A method to achieve this function will be introduced below.

First of all, let us first understand the knowledge related to the database. In MySQL, there is a keyword called "DISTINCT" that can remove duplicate parts from query results. So if we want to randomly extract non-duplicate data, we can first use the "DISTINCT" keyword to remove the duplicate parts of the original data, and then randomly extract one from the remaining data.

The following is a piece of PHP code to implement the above process:

<?php // 建立数据库连接
$conn = mysqli_connect(&#39;localhost&#39;, &#39;root&#39;, &#39;&#39;, &#39;test&#39;);

// 查询数据并去重
$sql = "SELECT DISTINCT name FROM users";
$result = mysqli_query($conn, $sql);

// 将查询结果存储在数组中
$data = array();
while ($row = mysqli_fetch_assoc($result)) {
    $data[] = $row[&#39;name&#39;];
}

// 随机取出一个不重复的数据
$random = array_rand($data);
echo $data[$random];

// 断开数据库连接
mysqli_close($conn);
?>

In the above code, the connection to the database is first established through the mysqli_connect() function, and the $sql statement is used to query Unduplicated data (assume here that there is a table named "users" in the database, and each row has a field named "name"). Then use the mysqli_fetch_assoc() function to save the query results into an array row by row. Finally, use the array_rand() function to randomly remove an element from the array and output the element.

It should be noted that in the above code, the query results can be stored row by row in the array only through the mysqli_fetch_assoc() function. And after using the mysqli_query() function, you need to close the database connection through the mysqli_close() function to avoid occupying system resources.

The above is a method of randomly selecting non-duplicate databases in PHP. Through this method, we can easily randomly retrieve non-duplicate data from a database and achieve more practical functions.

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