SELECT然后使用PHP将数据插入MySQL [关闭]

Question

I am trying to check if there is a entry from today and if not then add one, if it already exists then not. Current code is:

$conn = new mysqli($servername, $username, $password, $dbname);
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
} 

$sql .= "SELECT plusamount AS plustotal, minusamount AS minustotal FROM   Juuli WHERE reg_date >= CURRENT_DATE() ORDER BY id DESC";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    echo "It already exists!";
} else {
    echo "autowrite should run";
    $sql .= "INSERT INTO Juuli(minusamount) VALUES (0); ";
}
$conn->close();
?>

Answer 1

If your SELECT statement is working the way you want it to directly from the database, the following should work. (notice the replacement of .= with =)

$sql = "SELECT plusamount AS plustotal, minusamount AS minustotal FROM Juuli WHERE reg_date >= CURRENT_DATE() ORDER BY id DESC";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    echo "It already exists!";
} else {
    echo "autowrite should run";
    $sql2 = "INSERT INTO Juuli (minusamount) VALUES (0)";
    $result2 = $conn->query($sql2);
}
$conn->close();