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]'";