having trouble with mysql_num_rows

[ostig]

I am attempting to write a script to add or delete users from a database. I am very new to this so apologies if I missed something very basic, but I have been looking/recoding for hours...

 

Here is the code at present of the part that is at issue.

----------------------

if ($switch == "add") {

 

$query="INSERT INTO subscribers (userid, username, userpass)VALUES ('NULL','".$user1."', '".$pass1."')";

mysql_query($query) or die ('Error updating database');

echo "Database Updated With: " .$user1. " " .$pass1 ;

}

 

elseif ($switch == "del") {

 

$query="SELECT FROM subscribers WHERE (username=".$user1." AND userpass=".$pass1.")";

 

mysql_query($query);

 

if (mysql_num_rows($query) == FALSE) {

  echo "User / Password combination does not exist";

  }

  else {

  $query="DELETE FROM subscribers WHERE (username='".$user1."' AND userpass='".$pass1."')";

  mysql_query($query) or die ('Error deleting from database');

  echo "User " .$user1. "deleted";

  }

}

 

else {

echo "You did not specify to add or delete...";

}

 

---------------------------------------------

The part about adding works fine, if I put in a new userid and password and select add, the data gets added to the database.

 

However, if I put in a userid and password and select "del", I get errors when I am trying to use the mysql_num_rows function.

 

What I am trying to do is:

IF the username / password combo does not exist, just print out the message.

IF the userid / password combo does exist, delete the userid from the table.

 

On both of the above conditions, I get:

Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in /home/cheshire/public_html/test/update.php on line 36

 

( LINE 36 is (mysql_num_rows($query) != FALSE) { )

 

If the userid / password combo does not exist, I also get the appropriate message.

If the userid / password combo does exist, it is successfully deleted.

 

No matter how I change line 36 I still get this error. I would be more than willing to not use mysql_num_rows if there is another way to get this done, I was earlier advised to use this function to accomplish what I need to do.

 

Any help/advice appreciated.

 

Kevin

 

 

 

 

[lanmonkey]

do this:

 

if ($switch == "add") {

 

$query="INSERT INTO subscribers (userid, username, userpass)VALUES ('NULL','".$user1."', '".$pass1."')";

mysql_query($query) or die ('Error updating database');

echo "Database Updated With: " .$user1. " " .$pass1 ;

}

 

elseif ($switch == "del") {

 

$query="SELECT FROM subscribers WHERE (username=".$user1." AND userpass=".$pass1.")";

 

$result = mysql_query($query);

 

if (0 == mysql_num_rows($result)) {

  echo "User / Password combination does not exist";

  }

  else {

  $query="DELETE FROM subscribers WHERE (username='".$user1."' AND userpass='".$pass1."')";

  mysql_query($query) or die ('Error deleting from database');

  echo "User " .$user1. "deleted";

  }

}

 

else {

echo "You did not specify to add or delete...";

}

[ostig]

Edited code.

 

Result with mismatched userid/password:

version = 1.01

Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in /home/cheshire/public_html/test/update.php on line 38

User / Password combination does not exist

 

---------------------

echo "version = 1.01";

 

if ($switch == "add") {

 

$query="INSERT INTO subscribers (userid, username, userpass)VALUES ('NULL','".$user1."', '".$pass1."')";

mysql_query($query) or die ('Error updating database');

echo "Database Updated With: " .$user1. " " .$pass1 ;

}

 

elseif ($switch == "del") {

 

$query="SELECT FROM subscribers WHERE (username=".$user1." AND userpass=".$pass1.")";

 

$result = mysql_query($query);

 

if (0 == mysql_num_rows($result)) {

 

  echo "User / Password combination does not exist";

  }

  else {

  $query="DELETE FROM subscribers WHERE (username='".$user1."' AND userpass='".$pass1."')";

  mysql_query($query) or die ('Error deleting from database');

  echo "User " .$user1. "deleted";

  }

}

 

else {

echo "You did not specify to add or delete...";

}

[lanmonkey]

you might also have a problem with your sql query:

 

try putting single quotes around the variables:

 

$query="SELECT FROM subscribers WHERE (username='".$user1."' AND userpass='".$pass1."')";

 

more info: http://www.w3schools.com/php/php_mysql_where.asp