如何防止从csv到mysql的重复插入

How to prevent insert if email exist

if (isset($_REQUEST['btn_import']))
{
    $filename = 'Database.csv';
    $fp = fopen($filename, "r");
    while (($row = fgetcsv($fp, "40", ",")) != FALSE)
    {
        $sql = "INSERT INTO excel (name,email,phone_no) VALUES('" . implode("','", $row) . "')";
        if (!$conn->query($sql))
        {
            echo '<br>Data No Insert<br>';
        }
    }
    fclose($fp);
}

ps. this code its from stackoverflow

You have several ways to do this.

1. Clean your csv before trying to insert : $csv[$row[$emailColId]] = $row for example
2. Before every insert, use SELECT COUNT(*) WHERE email = $email
3. In your table definition, add an Index on email, set it to UNIQUE and deal with query() returning true / false or exceptions thrown

To me, the best choice would be the 3rd point.