duanbo1659 2014-12-28 15:47
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如何检查两个表中某些表中是否存在注册页面中的给定用户名

I want to check if the given username exists in at least one of the two given tables and if it is exists then it will shows them a message that the username already exists. I wrote some code using the UNION statement but it does not show me the message. Can you tell me please what is wrong with my code? Thanks

if (mysql_num_rows(queryMysql("SELECT * FROM doctor
                  WHERE username='$username' UNION SELECT * FROM patient
                  WHERE username='$username'")))
                $error = "That username already exists<br /><br />";
            else
              {
                queryMysql("INSERT INTO doctor (fname,lname,username,email,password,gender,age,specialty,doctorID) VALUES('$fname','$lname','$username','$email', '$password','$DoctorG','$DoctorAge','$specialty','$Doctor_ID')");
                die("<h4>Account created</h4>Please Log in.<br /><br />");
              }
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  • douning5041 2014-12-28 15:56
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    You can try the following:

    function exists( $detail, $table, $column, $value ) {
        $stmt = mysql_query("SELECT `$detail` FROM `$table` WHERE `$column` = '$value'");
    
        if( mysql_num_rows($stmt) >= 1 ) {
            return true;
        } else {
            return false;
        }
    }
    
    if( exists('username', 'doctor', 'username', $username) === false && exists('username', 'patient', 'username', $username) === false ) {
        echo 'user doesn\'t exists';
    } else {
        echo 'user exists';
    }
    

    You should really consider using mysqli_* or PDO instead of mysql_* since it is depracted and will be removed

    本回答被题主选为最佳回答 , 对您是否有帮助呢?
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