如果csv中的列小于或大于4，我如何发出警告并且不继续执行命令。我有这个代码导入我的csv，但我只需要4列，以避免不必要的值插入到mysql。

while(($csvdata = fgetcsv($handle,10000,","))!== FALSE){
        if($i>0) {
    $sha1 = $csvdata[0];
    $vsdt = $csvdata[1];
    $trendx  = $csvdata[2];
    $notes  = $csvdata[3];

    // Get record where sha1 
    $check_sha = "SELECT sha1 FROM jeremy_table_test WHERE sha1='".$sha1."'";
    $check_shaquery = mysqli_query($con , $check_sha);
    if($check_shaquery){
        $sha_count = mysqli_num_rows($check_shaquery);
    }

    // Check if sha1 already in database
    if(isset($sha_count) && $sha_count>0){
        $sql = "UPDATE `jeremy_table_test` SET `date_sourced`='".$date."',`sha1`='".$sha1."',`vsdt`='".$vsdt."',`trendx`='".$trendx."',`notes`='".$notes."' WHERE sha1='".$sha1."'";
        $query = mysqli_query($con , $sql);
    }else{
        $sql = "INSERT INTO jeremy_table_test (date_sourced,sha1,vsdt,trendx,notes) VALUES ('$date','$sha1','$vsdt','$trendx','$notes')";
        $query = mysqli_query($con , $sql);
    }

    $c = $c+1;
    error_reporting(E_ALL ^ E_NOTICE);
    }
        $i++;
        error_reporting(E_ALL ^ E_NOTICE);
    }

请告诉我怎么做。这是我唯一的问题