PHP code implements simple query function

(This article is for reference only. The code may have errors due to changes in time and versions. Readers are asked to adjust by themselves)

In website development, the query function is very common. I will share it with you below. Let’s look at the PHP code implementation of a simple query function.

First, create an input box and a submit button in the HTML file:

<form action="query.php" method="post">
  <input type="text" name="name" placeholder="请输入要查询的名字">
  <input type="submit" name="submit" value="查询">
</form>

Then, write the SQL statement in the query.php file and output the result:

<?php
  // 建立数据库连接
  $conn = mysqli_connect("localhost", "username", "password", "database_name");

  // 获取输入框中的名字
  $name = $_POST[&#39;name&#39;];

  // 查询语句
  $sql = "SELECT * FROM user WHERE name LIKE &#39;%$name%&#39;";

  // 执行查询
  $result = mysqli_query($conn, $sql);

  // 输出查询结果
  if(mysqli_num_rows($result) > 0) {
    while($row = mysqli_fetch_assoc($result)) {
      echo "名字：" . $row['name'] . "<br>";
      echo "年龄：" . $row['age'] . "<br>";
      echo "性别：" . $row['gender'] . "<br>";
      echo "<hr>";
    }
  } else {
    echo "查询结果为空！";
  }

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

Code explanation:

1. To establish a database connection, you need to fill in the corresponding database address, user name, password and database name.
2. Get the name in the input box through $_POST.
3. $sql is the query statement, LIKE represents fuzzy query, and % represents any character.
4. Execute the query and read the query results row by row through mysqli_fetch_assoc.
5. Output the query results and use while loop and mysqli_num_rows to determine whether the query results are empty.
6. Close the database connection and release resources.

This article only briefly introduces the PHP code implementation of the query function and does not include other security and optimization content. In actual development, you also need to pay attention to preventing security issues such as SQL injection, and optimizing the performance of query statements.

The above is the detailed content of PHP code implements simple query function. For more information, please follow other related articles on the PHP Chinese website!