SQL，在计算两次差异时插入表

Question

I'm currently using fullcalendar to make a simple calendar. My database has got three date-times:

start 
end
total

What I want is the program, as it inserts the date, to calculate the difference between start and end and add it to total. This is my SQL code for insertion:

I'm using InnoDB in MySQL.

session_start();

include_once './conexao.php';

$dados = filter_input_array(INPUT_POST, FILTER_DEFAULT);

//Converter a data e hora do formato brasileiro para o formato do Banco de Dados
$data_start = str_replace('/', '-', $dados['start']);
$data_start_conv = date("Y-m-d H:i:s", strtotime($data_start));

$data_end = str_replace('/', '-', $dados['end']);
$data_end_conv = date("Y-m-d H:i:s", strtotime($data_end));

$query_event = "INSERT INTO events (title, name, color, start, end, total) "
        . "VALUES (:title, :name, :color, :start, :end) "
        . "SELECT DATEDIFF(':start', ':end') AS total";

$insert_event = $conn->prepare($query_event);
$insert_event->bindParam(':title', $dados['title']);
$insert_event->bindParam(':name', $dados['name']);
$insert_event->bindParam(':color', $dados['color']);
$insert_event->bindParam(':start', $data_start_conv);
$insert_event->bindParam(':end', $data_end_conv);

if ($insert_event->execute()) {
    $retorna = ['sit' => true, 'msg' => '<div class="alert alert-success" role="alert">Evento inserido com sucesso!</div>'];
    $_SESSION['msg'] = '<div class="alert alert-success" role="alert">Evento inserido com sucesso!</div>';
} else {
    $retorna = ['sit' => false, 'msg' => '<div class="alert alert-danger" role="alert">Erro: Evento não foi inserido com sucesso!</div>'];
}


header('Content-Type: application/json');
echo json_encode($retorna);```

Answer 1

I can see just from looking that you must be experiencing a SQL syntax error - you can't use INSERT...VALUES and INSERT...SELECT syntax in the same query - you must use one or the other. But you don't need the SELECT here, you can just put the DATEDIFF function as one of the values. You also don't need quote marks round the parameters you pass to DATEDIFF.

You also can't use the same parameter name twice in PDO.

This should work better I think (although I'm not able to test it, obviously):

$query_event = "INSERT INTO events (title, name, color, start, end, total) "
        . "VALUES (:title, :name, :color, :start, :end, DATEDIFF(:start2, :end2))";

$insert_event = $conn->prepare($query_event);
$insert_event->bindParam(':title', $dados['title']);
$insert_event->bindParam(':name', $dados['name']);
$insert_event->bindParam(':color', $dados['color']);
$insert_event->bindParam(':start', $data_start_conv);
$insert_event->bindParam(':end', $data_end_conv);
$insert_event->bindParam(':start2', $data_start_conv);
$insert_event->bindParam(':end2', $data_end_conv);

PS If there are still other issues when you run the code you will need to explain it specifically, since you didn't mention them at the start.

Answer 2

[EDIT] I think this could do it :

INSERT INTO events (title, name, color, start, end, total) 
SELECT :title, :name, :color, t.start, t.end, DATEDIFF(t.start, t.end) )
FROM ( SELECT :start, :end) AS t

But you'll need to try to be sure.

Answer 3

Don't mix the Values clause and the Select clause in one insert statement. You have two alternatives:

$query_event = "INSERT INTO events (title, name, color, start, end, total) "
        . "VALUES (:title, :name, :color, :start, :end, DATEDIFF(':start', ':end')) "

$query_event = "INSERT INTO events (title, name, color, start, end, total) "
        . "SELECT :title, :name, :color, :start, :end, DATEDIFF(':start', ':end') AS total from dual";