Mysql「where」and「or」statement

Question

我開始在一個Mysql查詢上工作，它會一直出現一個錯誤？

有人可以看看它，並告訴我我做錯了什麼？

$query = ("select * from `users` where (`username`='$username' and `password`='$password' or select * from `users` where `$username `='$email' and `password`='$password')"); 

誤差

mysql_num_rows(): supplied argument is not a valid MySQL result resource in /home/a8423624/public_html/testchecklogin.php on line 57 

，這意味着它並沒有發現任何人。這意味着我的查詢是錯誤的？

Answer 1

的... OR SELECT...是給錯誤。我想你嘗試寫爲：

$query = ("select * from `users` where (`username`='$username' OR `$username `='$email') and `password`='$password'"); 

Answer 2

嘗試此查詢：

select * from `users` 
where 
(`username`='$username' or `username `='$email') and `password`='$password' 

Answer 3

作品！

SELECT * FROM "users" WHERE (username = '".$username."' OR username = '".$email."') AND password = '".$password."'";