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我正在尝试在我的网站上设置高级搜索,但是当用户提交搜索时,如果有一个空字段,它将作为 NULL 发送。我不确定如何排除空参数。

以下是搜索表格:

<form>
  <div class="form-group">
    <div class="col-sm-2">
      <label for="Author" class="control-label">Author</label>
    </div>
    <div class="col-sm-10">
      <input type="text" class="form-control" id="author" placeholder="Author" name="author">
    </div>
  </div>
  <div class="form-group has-feedback">
    <div class="col-sm-2">
      <label for="isbn" class="control-label">ISBN</label>
    </div>
    <div class="col-sm-10">
      <input type="text" class="form-control" id="isbn" placeholder="ISBN" name="isbn">
    </div>
  </div>
  <div class="form-group">
    <div class="col-sm-2">
      <label for="genre" class="control-label">Genre</label>
    </div>
    <div class="col-sm-10">
      <input type="text" class="form-control" id="genre" placeholder="Genre" name="genre">
    </div>
  </div>
  <div class="form-group">
    <div class="col-sm-2">
      <label for="tags" class="control-label">Tags</label>
    </div>
    <div class="col-sm-10">
      <input type="text" class="form-control" id="tags" placeholder="Tags" name="tags">
    </div>
  </div>
  <div class="form-group">
    <div class="col-sm-2">
      <label for="location" class="control-label">Location</label>
    </div>
    <div class="col-sm-10">
      <input type="text" class="form-control" id="location" placeholder="Location" name="location">
    </div>
  </div>

  <div class="form-group">
    <div class="col-sm-offset-2 col-sm-10">
      <button type="submit" name="AdvancedSearch" value="Search" class="btn btn-block btn-lg btn-primary">Search</button>

    </div>
  </div>
</form>

以下是查询:

$sql = "select *
          from Book_info
          where user_id=$u_id
            AND title like '%$_REQUEST[title]%'
            AND location like '%$_REQUEST[location]%'
            AND author like '%$_REQUEST[author]%'
            AND tags like '%$_REQUEST[tags]%'
            AND genre like '%$_REQUEST[genre]%'
             OR ISBN='$_REQUEST[isbn]'";
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1 回答 1

0

首先,我觉得我应该评论一下,比起将请求值直接注入查询字符串,更喜欢准备好的语句。

对您的问题最简单的解决方案是这样的:

<?php

$sql="select * from Book_info where user_id=$u_id";

$title = $_REQUEST['title'];
$location = $_REQUEST['location'];

if($title != null) {
    $sql .= " AND title like '%$title%'"; 
}

if($location != null) {
    $sql .= " AND location like '%$location%'";
}

//and so on...

这个想法是您检查该值是否为空,然后将一个新的 where 子句附加到您的查询中,只要该值不为空(或空或您要添加的任何其他谓词)。

于 2016-03-30T01:54:58.047 回答