如何进行有限的记录搜索？

Question

请帮帮我。在此代码中，用户将键入一个数字。然后在提交输入后，它应该搜索的唯一记录是 ID 号 1 到 143（不包括编号 144 及以上）。我该怎么做？它像一个范围吗？如何？谢谢！

<?php


$prevalue = $_POST['id_checknumber'];






$query = mysqli_query($link, "SELECT * FROM demo WHERE id_ln = '$prevalue'");

$numrows = mysqli_num_rows($query);



if ($prevalue <= 10){ 
    echo "<script>
             alert('Loric Number $prevalue has already been taken by a Garde.'); 
             window.history.go(-1);
    </script>";}
    else {
if ($numrows!=0){

while($row = mysqli_fetch_assoc($query)) {
   $id_ln = $row['id_ln'];
   $id_email = $row['id_email'];
   $id_firstname = $row['id_firstname']; 
   $id_lastname = $row['id_lastname']; 
   echo "<script>
             alert('Hi, $id_firstname $id_lastname! Your registered Loric Number is $id_ln. Thanks!'); 
             window.history.go(-1);
    </script>";
}}


if ($numrows===0){echo"<script>
             alert('Hi! This number is not yet registered. Register now! Go back to the main menu!'); 
             window.history.go(-1);
    </script>";
    }
}

mysqli_close($link);

?>

Answer 1

$query = mysqli_query($link, "SELECT * FROM demo WHERE id_ln = '$prevalue' AND id_ln <= 143");

我认为这应该可以回答您的问题，但正如人们已经在评论中所说，最好在尝试查询之前就禁止高于 143 的值。

当然，除非您只想返回前 143 条记录，否则它将如下所示：

$query = mysqli_query($link, "SELECT * FROM demo WHERE id_ln = '$prevalue' LIMIT 143");

如何进行有限的记录搜索？

How to do the limited record searching?

php

mysql

range