PHP MYSQL PREPARE synstax问题（意外的T_STRING）

I'm new to sql and PHP. So far have been able to figure things out but the PREPARE statement is giving me syntax issues (maybe because I'm trying to do several things in one step). If someone could let me know where my syntax is messing up that would be great.

In addition the code I'm writing is trying to update save files on a server and while I believe doing it with a prepare statement is the correct way I would be happy to hear if it is not. Note I plan to change INSERT INTO -> a conditional insert or update.

The error I get is unexpected T_STRING. I've marked the line of the error in the code.

$sql='PREPARE statement FROM "INSERT INTO buildings VALUES(?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?) WHERE id="$id" AND ind="$i""';
$result=mysql_query($sql);
for($i=0;$i<1600;$i+=1){
    if(isset($_POST['ind'.$i])){
        $bind=$_POST['bind'.$i];
        $time=$_POST['time'.$i];
        $level=$_POST['level'.$i];
        $p1ind=$_POST['p1ind'.$i];
        $p1state=$_POST['p1state'.$i];
        $p1time=$_POST['p1time'.$i];
        $p2ind=$_POST['p2ind'.$i];
        $p2state=$_POST['p2state'.$i];
        $p2time=$_POST['p2time'.$i];
        $p3ind=$_POST['p3ind'.$i];
        $p3state=$_POST['p3state'.$i];
        $p3time=$_POST['p3time'.$i];
        $p4ind=$_POST['p4ind'.$i];
        $p4state=$_POST['p4state'.$i];
        $p4time=$_POST['p4time'.$i];
        $p5ind=$_POST['p5ind'.$i];
        $p5state=$_POST['p5state'.$i];
        $p5time=$_POST['p5time'.$i];

        $sql = 'SET @bind="$bind",'. //<-line of error
        '@time="$time",'.
        '@level="$level",'.
        '@p1ind="$p1ind",'.
        '@p1state="$p1state",'.
        '@p1time="$p1time",'.
        '@p2ind="$p2ind",'.
        '@p2state="$p2state",'.
        '@p2time="$p2time",'.
        '@p3ind="$p3ind",'.
        '@p3state="$p3state",'.
        '@p3time="$p3time",'.
        '@p4ind="$p4ind",'.
        '@p4state="$p4state",'.
        '@p4time="$p4time",'.
        '@p5ind="$p5ind",'.
        '@p5state="$p5state",'.
        '@p5time="$p5time",'.
        '@id="$id",'.
        '@ind="$i"';
        $result=mysql_query($sql);
        $sql='EXECUTE statement USING @id,@time,@level,@p1ind,@p1state,@p1time,@p2ind,@p2state,@p2time,@p3ind,@p3state,@p3time,@p4ind,@p4state,@p4time,
        @p5ind,@p5state,@p5time,@ind,@bind';
        $result=mysql_query($sql);
        if(!$result){
            die("saveArry[0]=".mysql_error().";");
        }else{
            die("saveArry[0]='saved';");
        }
    }
}
$sql='DEALLOCA PREPARE statement';
$result=mysql_query($sql);

Update I am unable to install PDO on my hosts servers and therefore PDO is unfortunately an unacceptable solution. My answer (now with no errors!):

    if(isset($_POST['ind'])){
    $ind=sanitizeString($_POST['ind']);
    $bind=sanitizeString($_POST['bind']);
    $time=sanitizeString($_POST['time']);
    $level=sanitizeString($_POST['level']);
    $p1ind=sanitizeString($_POST['p1ind']);
    $p1state=sanitizeString($_POST['p1state']);
    $p1time=sanitizeString($_POST['p1time']);
    $p2ind=sanitizeString($_POST['p2ind']);
    $p2state=sanitizeString($_POST['p2state']);
    $p2time=sanitizeString($_POST['p2time']);
    $p3ind=sanitizeString($_POST['p3ind']);
    $p3state=sanitizeString($_POST['p3state']);
    $p3time=sanitizeString($_POST['p3time']);
    $p4ind=sanitizeString($_POST['p4ind']);
    $p4state=sanitizeString($_POST['p4state']);
    $p4time=sanitizeString($_POST['p4time']);
    $p5ind=sanitizeString($_POST['p5ind']);
    $p5state=sanitizeString($_POST['p5state']);
    $p5time=sanitizeString($_POST['p5time']);
    $rot=sanitizeString($_POST['rot']);
    $sql="INSERT INTO buildings (id,ind,bind,time,level,p1ind,p1state,p1time,p2ind,p2state,p2time,p3ind,p3state,p3time,p4ind,p4state,p4time,p5ind,
    p5state,p5time,rot) VALUES ('$id','$ind','$bind','$time','$level','$p1ind','$p1state','$p1time','$p2ind','$p2state','$p2time','$p3ind','$p3state',
    '$p3time','$p4ind','$p4state','$p4time','$p5ind','$p5state','$p5time','$rot') ON DUPLICATE KEY UPDATE bind='$bind',time='$time',level='$level',
    p1ind='$p1ind',p1state='$p1state',p1time='$p1time',p2ind='$p2ind',p2state='$p2state',p2time='$p2time',p3ind='$p3ind',p3state='$p3state',
    p3time='$p3time',p4ind='$p4ind',p4state='$p4state',p4time='$p4time',p5ind='$p5ind',p5state='$p5state',p5time='$p5time',rot='$rot'";
    $result=mysql_query($sql);
    if(!$result){
        die("saveArry[0]=".mysql_error().";");
    }else{
        die("saveArry[0]=saved;");
    }
}

The single and double quotes are interchanged in that line, should be,

 $sql = "SET @bind='$bind', 
    @time='$time',
    @level='$level',
    @p1ind='$p1ind',
    @p1state='$p1state',
    @p1time='$p1time',
    @p2ind='$p2ind',
    @p2state='$p2state',
    @p2time='$p2time',
    @p3ind='$p3ind',
    @p3state='$p3state',
    @p3time='$p3time',
    @p4ind='$p4ind',
    @p4state='$p4state',
    @p4time='$p4time',
    @p5ind='$p5ind',
    @p5state='$p5state',
    @p5time='$p5time',
    @id='$id',
    @ind='$i'";

I strongly recommend using PDO instead of deprecated mysql_* functions. It is doing the hard work with prepared statements for you transparently.

As EthanB pointed out in comment, your code is vulnerable to SQL injection as you are inserting the values directly from user input ($_POST variable).

With PDO your code would look something like this (simplified):

$statement = $pdo->prepare("INSERT INTO buildings VALUES(:ind, :bind, :time, :level, ...) WHERE id = :id AND ind = :ind");

for( ... ) {
    $statement->execute(array(
       ":ind" => $_POST["ind" . $i],
       ":bind" => $_POST["bind" . $i], ...
    ));
}

The PDO will send the PREPARE and EXECUTE queries for you and escape all parameters to prevent SQL injection.