How to solve a question about pdo

One question about pdo: PHPcodeif (isset ($ _ POST ['loginname']) & amp; isset ($ _ POST ['pwd']) & amp; & amp; $ _ POST ['action'] = 'submit ') {a question about pdo

PHP code

  If (isset ($ _ POST ['loginname']) & isset ($ _ POST ['pwd']) & $ _ POST ['action'] = 'submit ') {$ loginName = $ _ POST ['loginname']; $ pwd = $ _ POST ['pwd']; echo $ loginName. ''. $ pwd; $ SQL = "SELECT COUNT (*) FROM tb_esq WHERE login_name =: loginName AND pwd =: pwd"; require_once ('Conn. php '); $…… = $ db-> prepare ($ SQL); $……> bindParam (': loginname', $ loginName, PDO: PARAM_STR, 25 ); $ Something-> bindParam (': pwd', $ pwd, PDO: PARAM_STR, 25); $ Something-> execute (); $ rowCount = $ Something-> fetchColumn (); var_dump ($ rowCount ); // Always 0 $ db = NULL; if ($ rowCount = 1) {echo "script window. location = \ "index.html \"; script ";} else {alert ('user name or password is incorrect! '); Echo "script window. location = \" login. php \ "; script";}

After submitting the username and password in the database, the system prompts that the password is incorrect. why?

------ Solution --------------------
Use a common query to check whether data can be obtained.

PHP code

$sql = "SELECT COUNT(*) FROM tb_esq WHERE login_name = '$loginName' AND pwd = '$pwd'";$result = $db->query($sql);$row = $result->fetch(PDO::FETCH_ASSOC);print_r($row);