我做了一個帶有投票系統的小型php網站。 我使用PDO撥打了我的sql調用,但無法檢查一個人是否每天不能爲相同類別投票兩次。我如何檢查選擇查詢是否提供任何數據?
下面你會發現我的php代碼和sql表。
<?php
header("Expires: Tue, 01 Jan 2000 00:00:00 GMT");
header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
header("Cache-Control: no-store, no-cache, must-revalidate,max-age=0");
header("Cache-Control: post-check=0, pre-check=0", false);
header("Pragma: no-cache");
session_start();
$user = $_SESSION['username'];
try {
$db = new PDO('mysql:host=localhost;dbname=xxxxxxxx',"xxxxxxxxx", "xxxxxxxxxx");
}catch (PDOException $e){
echo $e->getMessage();
}
$aantalRijen = $db->query("SELECT gebruiker FROM stem WHERE UPPER(gebruiker) = '$user' AND UPPER(categorie)='dick' AND datum = CURDATE()");
$sql = "INSERT INTO stem (categorie, naam, commentaar, datum, gebruiker)
VALUES('dick','$_POST[naam]','$_POST[commentaar]',CURDATE(), '$user')";
if($aantalRijen > 0) {
echo nl2br("U heeft al een stem uitgebracht \n");
echo "<script>setTimeout(\"location.href = 'index.php';\",1500); </script>";
}
else {
$results = $db->exec($sql);
echo "Stem succesvol uitgebracht!";
echo "<script>setTimeout(\"location.href = 'index.php';\",1500); </script>";
}
$results = NULL;
$aantalRijen = NULL;
$db = NULL;
?>
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使用'if(count($ aantalRijen)> 0){' – Saty