Question

我正在尝试制作一个简单的if else语句，但我无法获得所需的结果，显然使用了错误的方法。

这就是我所拥有的：

if (!$res7 and !$res8) {output one - this should appear if both $res7 and $res8 are empty}

else if (!$res8)  {output two - this should appear if $res8 is empty}

else if (!$res7) {output three - this should appear if $res7 is empty}

输出显示我想要的东西，有人可以帮忙解决它吗？感谢

编辑完整代码：$ res7和$ res8是MySQL查询的结果

$res8 = $pdo->query($query8);

if (empty($res7) && empty($res8)) {

printf("We currently have no reviews for this park or its attractions. If you have been to %s please take a minute to give your feedback. You don't need to register to leave reviews or ratings. Thank you." . PHP_EOL, $row[name]);
}

elseif (empty($res8)) {

printf("We currently have no attraction reviews for this park. If you have been to %s please take a minute to give your feedback. You don't need to register to leave reviews or ratings. Thank you." . PHP_EOL, $row[name]);

}

elseif (empty($res7)) {

printf("<h3>Park Review</h3>We currently have no reviews for this park as a whole. If you have been to %s please take a minute to give your feedback. You don't need to register to leave reviews or ratings. Thank you." . PHP_EOL, $row[name]);
}

else { 
printf("all good");
}

Answer 1

这是您初始化$res8

的方式

$res8 = $pdo->query($query8);

此时，$res8是一个结果集，包含查询结果。您要做的是检查结果集是否为空。您无法在其上调用empty()，因为即使没有结果，它仍然是结果集，因此它在您的通话中返回FALSE。

您需要做的是使用内置函数来查看它包含的行数：

if ($res8->rowCount() == 0) {
    ....

Answer 2

如果你的意思是空empty而不是false，那么就这样做：

if (empty($res7) && empty($res8)) {
    // First case
} elseif (empty($res8)) {
    // Second case
} elseif (empty($res7)) {
    // Third case
} else {
    // Not $res7 nor $res8 are empty
}

简单的PHP如果逻辑不起作用

2 个答案: