php怎么样判断多个post值是否为空

<form action="add.php" method="post"><br data-filtered="filtered">
<input type="text" name="name"><br data-filtered="filtered">
<input type="text" name="name2"><br data-filtered="filtered">
<input type="text" name="name3"><br data-filtered="filtered">
<input type="text" name="name4"><br data-filtered="filtered">
<input type="text" name="name5"><br data-filtered="filtered">
</form><br data-filtered="filtered">
<br data-filtered="filtered">
<?php<br data-filtered="filtered">
$name1=$_POST[name1];<br data-filtered="filtered">
$name2=$_POST[name2];<br data-filtered="filtered">
$name3=$_POST[name3];<br data-filtered="filtered">
$name4=$_POST[name4];<br data-filtered="filtered">
$name5=$_POST[name5];<br data-filtered="filtered">
<br data-filtered="filtered">
//插入数据库,如果是就单独判断一个变量，可以用IF，那如果多个怎么办呢<br data-filtered="filtered">
if($name1==''){<br data-filtered="filtered">
   echo '请输入数据';<br data-filtered="filtered">
   exit;<br data-filtered="filtered">
}<br data-filtered="filtered">
<br data-filtered="filtered">
$sql="insert into book values('$name1','$name2','$name3','$name4','$name5')";<br data-filtered="filtered">
mysql_query($sql);<br data-filtered="filtered">
<br data-filtered="filtered">
?>

//设$_POST = array('name' => '', 'name2' => 'e','name3' => 'r','name4' => '','name5' => ' ');
$t = array_keys($_POST, '');//如果空格不算空，就用这条
$t = array_keys(array_map('trim', $_POST), '');//如果空格算空，就用这条
if($t) 
{ //有空数据项  
print_r($t); //值就是为空的项}

if($name1=='' || $name2="" || $name3=""){  
    echo '请输入数据';  
    exit;  
 }

 <form action="add.php" method="post">
<input type="text" name="name[]">
<input type="text" name="name[]">
<input type="text" name="name[]">
<input type="text" name="name[]">
<input type="text" name="name[]">
</form>
  
<?php
//这里的$name将会得到一个数组
$name=$_POST['name'];
foreach ($name as $value)
{
   if($value=="")
   {
    echo "不能有空值";
    exit();
     }
}
 
$sql="insert into book values('$name[0]','$name[1]','$name[2]','$name[3]','$name[4]')";
mysql_query($sql);
  
?>