如何在PHP中获取select count(*)查询的结果？

Question

我在PHP中使用此查询:

mysql_query("select count(*) from registeredUsers where email=".$_SESSION["username"]);

当我echo用来打印结果时,没有任何内容被打印出来.上述声明的返回值究竟是什么？

Answer 1

您的代码不包含任何提取语句.而另一个答案指出,你需要单引号$_SESSION["username"].

$result = mysql_query("select count(*) from registeredUsers where email='{$_SESSION['username']}'");

// Verify it worked
if (!$result) echo mysql_error();

$row = mysql_fetch_row($result);

// Should show you an integer result.
print_r($row);

Answer 2

mysql_query返回结果资源.您可以阅读结果mysql_result

$res = mysql_query("select count(*) from registeredUsers where email='".mysql_real_escape_string($_SESSION["username"])."'");
echo mysql_result($res,0);