在PHP中嵌套的foreach循环进行查询

Question

Im trying to insert data in my db. It should look something like this --

     a_id=1 s_id=1 q_id=1
     a_id=1 s_id=1 q_id=2
     a_id=1 s_id=2 q_id=1
     a_id=1 s_id=2 q_id=2

right now it inserts something like this --

     a_id=1 s_id=1 q_id=null
     a_id=1 s_id=2 q_id=null
     a_id=1 s_id=1 q_id=1
     a_id=1 s_id=1 q_id=2
     a_id=1 s_id=2 q_id=1
     a_id=1 s_id=2 q_id=2

I have been beating my head around it for quite a long time. Please let me know if some one can shed some light on this. Here's my code --

    $aid=$_GET['id'];
    $sdata=XYZ::model()->findAll('a_id=:aid',array(':aid'=>$id));
    $qdata=ABC::model()->findAll('a_id=:aid',array(':aid'=>$id));
    $sql='insert into assignment_answers
                (a_id, s_id, q_id)
                values (:aid, :sid, :qid)';
            $command1=$connection->createCommand($sql);
            foreach($sdata as $sd)
            {
                foreach($qdata as $qd)
                {
                    $sid=$sd->id;
                    $command1->bindParam(":sid",$sid,PDO::PARAM_STR);
                    $qid=$qd->id;
                    $command1->bindParam(":qid",$qid,PDO::PARAM_STR);
                    $command1->bindParam(":aid",$aid,PDO::PARAM_STR);
                    $command1->execute();
                }
            }

Answer 1

You need 3 foreach loops: 1 for $adata, 1 for $sdata & 1 for $qdata.

$sql='insert into assignment_answers
            (a_id, s_id, q_id)
            values (:aid, :sid, :qid)';
$command1=$connection->createCommand($sql);
foreach($adata as $ad)
{
    foreach($sdata as $sd)
    {
        foreach($qdata as $qd)
        {
            $command1->bindParam(":aid",$ad->id,PDO::PARAM_STR);
            $command1->bindParam(":sid",$sd->id,PDO::PARAM_STR);
            $command1->bindParam(":qid",$qd->id,PDO::PARAM_STR);
            $command1->execute();
        }
    }
}

I assumed you also have a $adata set like $sdata & $qdata.