您正在将字符串与数组进行比较。你应该像这样使用in_array
<select id="space" name="space"> <option value="--Select--">--Select--</option> <?php $select=mysqli_query($con,"select * from clients where Space IS NOT NULL"); while($menu1=mysqli_fetch_array($select)) { $filled =$menu1['Space']; $valuez = array("C101","C102","C103","C104"); foreach($valuez as $value){ if($value != $filled){ ?> <option value="<?php echo $value;?>"> <?php echo $value;?> </option> <?php } }}?>更新代码
