从for循环或foreach的数组中插入php中的多个sql语句

Question

This is my code I have to insert an array each value in the insert statement

if(isset($_POST['add'])){
    $batch = $_POST['batch'];
    $course = explode(':', $_POST['course']);
    $cid = $course[0];
    $rowCount = count($_POST['branch']);
    $branch = implode(',', $_POST['branch']);
    $semester = $_POST['sem'];
    $day = $_POST['day'];
    $hour = $_POST['hour'];


    for($i=0;$i<$rowCount;$i++){
        $description = $_POST['branch'][$i];
        $sql. = "INSERT INTO batch (batch,bdescription,branch,course,semester,day,hour,user) VALUES ('$batch','$description',$i,'$cid','$semester','$day','$hour','$usnid');";

    }


    if($conn->query($sql)){
        $_SESSION['success'] = 'batch  added successfully';
    }
    else{
        $_SESSION['error'] = $conn->error;
    }
}

Please help thanks

Answer 1

You can't execute multiple queries with a single call to $conn->query() .

Change your query so it's just a single INSERT statement with multiple lists of values after VALUES .

$sql = "INSERT INTO batch (batch,bdescription,branch,course,semester,day,hour,user) VALUES "
for($i=0;$i<$rowCount;$i++){
    $description = $_POST['branch'][$i];
    $sql. = "('$batch','$description',$i,'$cid','$semester','$day','$hour','$usnid'),";
}
$sql = substr($sql, 0, -1); // remove last comma

You should also use $conn->real_escape_string() to escape all the inputs, to protect against SQL injection (it would be even better to do that with a prepared statement, but it's difficult to make a prepared statement in mysqli with dynamic parameters).

Answer 2

Barmar is correct, you can't execute multiple SQL statements with query() . There's mysqli_multi_query() , but there's hardly ever a justification for using that. The former Engineering Director for MySQL once told me unequivocally, "there's no reason for multi-query to exist."

You should use parameters instead of copying $_POST variables directly into your SQL strings. It's not hard, in fact it makes code easier than fiddling with confusing quotes-within-quotes and mysqli_real_escape_string() and so on.

I wouldn't bother with trying to insert multiple tuples in a single INSERT statement. How many branches can possibly be in a single POST? A few dozen at most? Not enough to make it necessary to make the INSERT into a single statement. So just call execute() for a prepared INSERT, once for each row.

$sql = "INSERT INTO batch 
        SET batch=?, bdescription=?, branch=?, course=?, semester=?,
            day=?, hour=?, user=?";
$stmt = $conn->prepare($sql) or die($conn->error);

$description = '';
$stmt->bind_param('ssssssss', $batch, $description, $i, $cid, $semester, $day, $hour, $usnid);

for($i=0;$i<$rowCount;$i++){
    $description = $_POST['branch'][$i];
    $stmt->execute() or die($stmt->error);
}

Read the manual for https://www.php.net/manual/en/mysqli-stmt.bind-param.php for more code examples.

Answer 3

This is how I Fixed My Code. I Used for loop

    if(isset($_POST['addstd'])){
    $rowCount = count($_POST['student']);

        for($i=0;$i<$rowCount;$i++){
            $stdid = $_POST['student'][$i];
            $course = $_POST['course'][$i];
            $batch = $_POST['batch'][$i];
            $branch = $_POST['branch'][$i];
            //insert students into attendance table

            $sqlsel =  "SELECT year,student_id, student_rollno,firstname,lastname, branch,active, nr FROM student WHERE student.student_id = '$stdid' AND student.branch = '$branch'";
            $querysel = $conn->query($sqlsel) or die($conn->error);
            $rowsel = $querysel->fetch_assoc();
                if($rowsel !== null){
                    $year = $rowsel['year'];
                    $rollno = $rowsel['student_rollno'];
                    $active = $rowsel['active'];        
                    $branch = $rowsel['branch'];
                    $name = $rowsel['firstname'].$rowsel['lastname'];


            $sql = "INSERT IGNORE INTO class (year,regno, rollno,name, programme,coursecode,batch,user,active,count) VALUES ('$year','$stdid','$rollno','$name','$branch','$course','$batch','$usnid','$active','$i');";

            if($conn->query($sql)){
                $_SESSION['success'] = 'Students Added To Batch Successfully';
            }
            else{
                $_SESSION['error'] = $conn->error;
            }
            }
                else{
                    continue;
                }
        }

}
else{
    $_SESSION['error'] = 'Fill up add form first';
}