Fuzzy query for PHP function application

PHP is a server-side scripting language widely used in web development. Developers can use PHP to build dynamic pages and applications. Functions are one of the key elements in the PHP language. They allow you to write code more efficiently and improve code reusability. This article will introduce fuzzy query, one of the PHP functions, and its application in actual development.

What is fuzzy query?

Fuzzy query is a query method used in database search. It can match some specified keywords to search for more results. In some cases, we need to find similar data, but due to too much data or character format limitations of the data, a single query cannot meet the needs. At this time, we can use fuzzy query to find relevant data through keyword fuzzy matching.

In PHP, we can implement fuzzy queries by using the LIKE operator. The LIKE operator can be used with wildcards. The wildcards include % and _, where % represents any number of characters and _ represents a single character. .

Specific Application

In actual development, fuzzy queries are widely used, such as:

1. Search engine: Search engine can be based on the similarity of keywords and content Search by degree
2. Username query: In the case of a large increase in users, fuzzy queries can be performed based on usernames to quickly find relevant users
3. Product query: In e-commerce websites, you can use Fuzzy query to classify products of the same category and brand

The following is a specific implementation of fuzzy query. We use PHP language and MySQL database to implement a simple fuzzy query function.

1. First, we need to connect to the MySQL database. Here we use the MySQLi function library to achieve:

//配置数据库连接信息
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";

//创建连接
$conn = new mysqli($servername, $username, $password, $dbname);

//检测连接
if ($conn->connect_error) {
   die("连接失败: " . $conn->connect_error);
}

2. Next, we need to query the table to satisfy Conditional data, here we take querying the user table as an example:

//获取用户输入的查询条件
$search_text = $_GET['search_text'];

//查询语句
$sql = "SELECT * FROM users WHERE username LIKE '%$search_text%'";

//执行查询语句
$result = $conn->query($sql);

In the above code, $search_text is the query condition entered by the user, and we use it in the query statement of the fuzzy query.

3. Finally, we need to traverse the query results and output each matching result in turn:

//判断查询结果是否为空
if ($result->num_rows > 0) {
   // 输出每行数据
   while($row = $result->fetch_assoc()) {
      echo "用户名：" . $row["username"]. "<br>";
      echo "密码：" . $row["password"]. "<br>";
      echo "邮箱：" . $row["email"]. "<br>";
   }
} else {
   echo "没有查询到相关用户！";
}

In the above code, we use the fetch_assoc() function to The query results are stored as an associative array, and then in the traversal output, information such as user name, password, and email address are output in sequence.

Summary

This article introduces fuzzy query, one of the functions in PHP, and demonstrates its application through a simple example. It should be noted that in actual development, in order to avoid security issues such as SQL injection, the query conditions entered by the user need to be judged and filtered for legitimacy. The above is the entire content of this article, I hope it will be helpful to PHP beginners.

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