PHP，SQL插入无效

Question

i would like to know why i am not able to insert new data to my Database. in vardump i get good result but nothing is added to my database

Database : c_id = AutoInc. | a_id | u_id | c_head | c_content | c_date =TIMESTAMP

if (isset($_POST['c_submit'])) {
   $sql_najdi_prihlaseneho_uzivatela = "SELECT * FROM users where u_name = '$_SESSION[username]'";
   $vysledokHladania = mysqli_query($connect_to_db, $sql_najdi_prihlaseneho_uzivatela);
   if (mysqli_num_rows($vysledokHladania) == 1) {
       while ($db_data_prihlaseneho_uzivatela = mysqli_fetch_assoc($vysledokHladania)) {
            $sql_vloz_komentar = "INSERT INTO comments (a_id, u_id, c_head, c_content, c_date) VALUES ($_GET[a_id], $db_data_prihlaseneho_uzivatela[u_id], $_POST[c_hlavicka], $_POST[c_obsah], 'NOW()')";
            mysqli_query($connect_to_db, $sql_vloz_komentar);
        }
    }
}

Answer 1

You can use date('Ymd h:i:s') to store current date time in our DB by PHP code and in your query you just missed to put '' in array index.
Try this one

if (isset($_POST['c_submit'])) {
    $date=date('Y-m-d h:i:s');
    $sql_najdi_prihlaseneho_uzivatela = "SELECT * FROM users where u_name = '".$_SESSION['username']."'";
    $vysledokHladania = mysqli_query($connect_to_db, $sql_najdi_prihlaseneho_uzivatela);
    if (mysqli_num_rows($vysledokHladania) == 1) {
        while ($db_data_prihlaseneho_uzivatela = mysqli_fetch_assoc($vysledokHladania)) {
            $sql_vloz_komentar = "INSERT INTO comments (a_id, u_id, c_head, c_content, c_date) VALUES 
                                (".$_GET['a_id'].",".$db_data_prihlaseneho_uzivatela['u_id']." ,".$_POST['c_hlavicka']." ,".$_POST['c_obsah']." ,$date)";
            mysqli_query($connect_to_db, $sql_vloz_komentar);
        }
    }
}

I thing it will help you.

Answer 2

do you escape the varchar character ? Other posible error is the date format in database. Post echo $sql_vloz_komentar for view the insert statement and the structure of table

if (isset($_POST['c_submit'])) {
   $sql_najdi_prihlaseneho_uzivatela = "SELECT * FROM users where u_name = '$_SESSION[username]'";
   $vysledokHladania = mysqli_query($connect_to_db, $sql_najdi_prihlaseneho_uzivatela);
   if (mysqli_num_rows($vysledokHladania) == 1) {
       while ($db_data_prihlaseneho_uzivatela = mysqli_fetch_assoc($vysledokHladania)) {
            $sql_vloz_komentar = "INSERT INTO comments (a_id, u_id, c_head, c_content, c_date) VALUES ($_GET[a_id], $db_data_prihlaseneho_uzivatela[u_id], '$_POST[c_hlavicka]', '$_POST[c_obsah]', 'NOW()')";
            mysqli_query($connect_to_db, $sql_vloz_komentar);
        }
    }
}