[RESOLVED] query is "invisible"

gilk9

Hi,
the following query appears to be invisible to the program....
ie it does not appear to be executed....no echos

	// open the connection

$conn = mysql_connect("h41mysql45.secureserver.net", "ezevetdistanceed", "password");

// pick the database to use

mysql_select_db("ezevetdistanceed",$conn) or die(mysql_error());

// create the SQL statement

$getsomething = "SELECT  * FROM studentanswers"; 	
$result = mysql_query($getsomething, $conn) or die(mysql_error("cant access student answers"));	
$numberofrows = mysql_num_rows($result);
echo "the number of rows is $numberofrows";


echo "got thru to studentanswers";

all of the subsequent queries are executed, so I think that $conn is OK.
the server and database and password must also be OK....so why the invisibility anyone??? PLEASE?
gilk9

Piranha

Exactly what do you mean with invisible? Do you get any output at all?

I see that you have two echo's, does it output "ghe number of rows is ", does it output "ght thru to studentanswers" or none of the above?

Is this in a function? If so, are you sure the function are executed?

When you do "echo $getsomething" and use the query in a database handler, do you get some result?

Another thing, do you actually use the values that are returned or do you only want the number of rows? If you only use the number of rows you should let the database count for you "select count(*) from studentanswers".

gilk9

Piranha wrote:
Exactly what do you mean with invisible? Do you get any output at all?

NONE the program just gets on with executing all that follows correctly

I see that you have two echo's, does it output "ghe number of rows is ", does it output "ght thru to studentanswers" or none of the above?
Neither echo is seen

Is this in a function? If so, are you sure the function are executed?
not a function

When you do "echo $getsomething" and use the query in a database handler, do you get some result?
dont have a database handler

Another thing, do you actually use the values that are returned or do you only want the number of rows? If you only use the number of rows you should let the database count for you "select count(*) from studentanswers"

Thanks for that, I just put the num of rows in place of other stuff to simplify and try to find why nothing happens....the student answers is used elsewhere later on and is Not Invisible!
.

Thanks for that, and hope this sheds some light on the error
I dont even get any error messages....!!!!

Piranha

Really strange problem. What version of PHP do you use? What version of MySQL?

With a database handler I mean something like phpmyadmin, it is a good PHP interface for MySQL databases.

I can't seem to find anything strange in the code you posted. Can you post the whole code, then it is possible that someone will find out why it doesn't seem to be working. Or even better, check if it works with only the code you have posted (in other words without any additional code).

gilk9

Piranha wrote:
Really strange problem. What version of PHP do you use? What version of MySQL?
5.0 and 4.0 respectively

With a database handler I mean something like phpmyadmin, it is a good PHP interface for MySQL databases.
will check that out

I can't seem to find anything strange in the code you posted. Can you post the whole code, then it is possible that someone will find out why it doesn't seem to be working. Or even better, check if it works with only the code you have posted (in other words without any additional code)
I have already stripped out all the other code and all that happens is that I get a blank screen when the remaining code is called ...not even an error message???????
.

here is the stripped down code....

<?php

session_start();

// open the connection

$conn = mysql_connect("h41mysql45.secureserver.net", "ezevetdistanceed", "password");

// pick the database to use

mysql_select_db("ezevetdistanceed",$conn) or die(mysql_error());

// create the SQL statement

$getsomething = "SELECT * FROM 'studentanswers'"; 	
$result = mysql_query($getsomething, $conn) or die(mysql_error("cant access student answers"));	
$numberofrows = mysql_num_rows($result);
echo "the number of rows is $numberofrows";
echo "got thru to studentanswers";	
?>

got me beat ..its now midnite...so will look for some inspiration from the forum in the (our) morning
Cheers
gilk9

laserlight

$getsomething = "SELECT * FROM 'studentanswers'";

should be:

$getsomething = "SELECT * FROM studentanswers";

studentanswers is your table name, but 'studentanswers' is a string.

However, in this case it is better to just write:

$getsomething = "SELECT COUNT(*) FROM studentanswers";

Now, the result you want is immediately available as a single value, instead of the whole table (and thus having to count the number of rows in that table result set yourself).

gilk9

Thanks for that Laserlight.....actually the first code example in the thread was the offending one...and it had the table name written correctly. I dont know where the string popped ino that later example.
Anyway when table name written correctly it as if the connection is not being made yet no error message is thrown up, and no echo is displayed. Very irritating. The connection code is a copy/paste of that used successfully elsewhere in the prog.
When I substitute your line
$getsomething = "SELECT COUNT(*) FROM studentanswers";
and echo the result....still nothing
so I think the problem must be in the connection, because the table exists and has around 900 rows and is INSERTed INTO, and SELECTed from successfully elsewhere using the same connection code.
I am at a loss!

NogDog

Couple things to try: make sure errors are being displayed, and check the result of your mysql_connect().

<?php
// for now, make sure all errors are displayed:
ini_set('display_errors', 1);
error_reporting(E_ALL);

session_start();

// open the connection

$conn = mysql_connect("h41mysql45.secureserver.net", "ezevetdistanceed", "password") or
      die("DB connection failed: " . mysql_error());

gilk9

did that and got
Parse error: parse error, unexpected T_STRING in /home/content/g/i/l/gilk99/html/testing.php on line 2

Hmmmm! more and more curious

laserlight

What is the exact code that you used?

gilk9

Maybe this problem is not due to the code?
The reason I suggest this possibility is that I have reduced the problem to the following 2 sets of code....one which works and one which doesnt work.
The problem is that I cant see any difference between the 2.
If I copy "workingcode.php" into my program the program works
If I copy "non-workingcode.php" into my program the program wont work but doesnt throw any errors either....seems invisible!!!
workingcode.php

<?php
session_start();
// open the connection
$conn = mysql_connect("h41mysql45.secureserver.net", "ezevetdistanceed", "password");
// pick the database to use
mysql_select_db("ezevetdistanceed",$conn);
// create the SQL statement
$sql = "SELECT * FROM studentanswers WHERE studentid = '$studentid' and quiznum = $_POST[quiznumber]";
// execute the SQL statement
$result = mysql_query($sql, $conn) or die(mysql_error());
/* Display results in a table */
  echo "<table cellspacing='15'>";
  echo "<tr><td colspan='4'><hr></td></tr>";
  while ($row = mysql_fetch_array($result))
  {
     extract($row);
      echo "<tr>\n
           <td>$quiznum</td>\n
           <td>$datetime </td>\n
           <td>$passfail</td>\n
           <td>$num_wrong</td>\n
           </tr>\n";
     echo "<tr><td colspan='4'><hr></td></tr>\n";
  }
  echo "</table>\n";
?>

and the non-workingcode.php

<?php
session_start();
// open the connection
$conn = mysql_connect("h41mysql45.secureserver.net", "ezevetdistanceed", "password");
// pick the database to use
mysql_select_db("ezevetdistanceed",$conn);
// create the SQL statement
$sql = "SELECT * FROM studentanswers WHERE studentid = '$studentid' and quiznum = $_POST[quiznumber]";
// execute the SQL statement
$result = mysql_query($sql, $conn) or die(mysql_error());
/* Display results in a table */
  echo "<table cellspacing='15'>";
  echo "<tr><td colspan='4'><hr></td></tr>";
  while ($row = mysql_fetch_array($result))
  {
     extract($row);
      echo "<tr>\n
           <td>$quiznum</td>\n
           <td>$datetime </td>\n
           <td>$passfail</td>\n
           <td>$num_wrong</td>\n
           </tr>\n";
     echo "<tr><td colspan='4'><hr></td></tr>\n";
  }
  echo "</table>\n";
?>

Now as far as I can see the snippets are identical. I hope someone can spot a difference.
The only difference in the snippets is that the one that works was written from scratch, while the one that doesnt was derived from copy and pasting bits of code from here and there. I suspect that there must be hidden tags or remnants that I cannot see. I am using EditPad Pro as my php editor...could this be a problem???

I really do appreciate coments and suggestions from the php community. just hope I can get this peculiar issue fixed.
Thanx

PS: Have just performed a file comparison on the 2 files above and EditPad Pro says that they are in fact identical......yet when I copy the Nonworking version then PHP just seems to ignore it.....got me scratching the old head!!@#$$@#

gilk9

laserlight wrote:
What is the exact code that you used?

Was trying out the error code suggested by NOG DOG above!
that is what produced the parse error
thanx

laserlight

Was trying out the error code suggested by NOG DOG above!
that is what produced the parse error

The parse error does not make sense in Nog Dog's code. As far as I can tell, that code snippet is perfectly fine.

Have just performed a file comparison on the 2 files above and EditPad Pro says that they are in fact identical......yet when I copy the Nonworking version then PHP just seems to ignore it

That is not possible. Do any of the PHP scripts you write from scratch work?

Piranha

Well, it seems like you have managed to solve the problem now, although you don't know what caused it.

Another thing that I spotted in your code: you are vunrable to SQL injection. Read up on it and how to solve it, a good place is the articles on phpbuilder.com.

gilk9

laserlight wrote:
The parse error does not make sense in Nog Dog's code. As far as I can tell, that code snippet is perfectly fine.

That is not possible. Do any of the PHP scripts you write from scratch work?

As you say "it is not possible" yet it is what happens. That is why I am asking in this forum.
It does happen. It is happening and that is why I am asking whether there could be some other cause ( see post #11 ) than bad/wrong PHP code.
ie could it be a problem with copy/paste of which I am not aware?
ie could it be a problem with EditPad Pro?
ie could there be a problem with php version changes on my host?

The longer I live the more I realise that "it is not possible" does not always apply.
There is always an answer or reason, it is not always immediately apparent.
I am new to PHP, but have been writing code for commercial applications since the late 1970s .

As for your question whether any of my php scripts work...yes I have a commercial php/mysql application running at present, it runs well even tho my php/mysql skills are not brilliant, it is just now when I came to add a new feature that things started to behave in a "not-possible" way!!!
Thanx

laserlight

could it be a problem with copy/paste of which I am not aware?

No. What might be a problem are things like character encoding and hidden characters. However, since your code is pretty much only in ASCII, that should not be a problem. Perhaps the line ending sequences, but even then I do not recall such problems where web servers are concerned. You could double check for hidden characters with a hex editor, and your text editor should be able to detect and control the character encoding and line ending sequences.

could it be a problem with EditPad Pro?

Perhaps, but if you used both code examples with EditPad Pro, then they should be corrupted in the same way. I might suspect that the file comparison algorithm did not take everything into account, so it is misleading you. In any case I took an MD5 hash of your two code examples, and the hashes match. Unfortunately, that only proves that the code examples as posted are the same.

could there be a problem with php version changes on my host?

No, since in such a case both code examples would not work. Since you have a version that works, the problem must lie with your code, not the server.

The longer I live the more I realise that "it is not possible" does not always apply.
There is always an answer or reason, it is not always immediately apparent.

Indeed, my claim of "that is not possible" only applies to the information that you have provided.

I have a commercial php/mysql application running at present, it runs well even tho my php/mysql skills are not brilliant, it is just now when I came to add a new feature

hmm... even when you edit existing code the problems occur? I had the impression that the problems arise when you create your own files with PHP code.

gilk9

Thanks for taking the time to check the 2 snippets.
I will just have to add the feature in another way.
I will get back to let you know IF there is an outcome.
Fortunately I am attempting these mods on a different host so that I dont stuff up my users.
Cheers,
gilk9

laserlight

Fortunately I am attempting these mods on a different host so that I dont stuff up my users.

If you can, test on your local computer, and configure it to be similiar to your host's setup.

gilk9

If I write a php script in NOTEPAD it works as expected.
If I open that script in EDITPAD PRO, save it, and FTP it I get all sorts of errors.
If I then open that offending script in NOTEPAD again and FTP it everything is fine.
The problem is that both scripts appear the same to the eye, even just a small four line script such as

<?php
session_start();
echo time() ;
?>

gets corrupted somehow with EDITPAD PRO.

So I suppose this is a resolution of sorts......anyone have a php editor recommendation that colors syntax that doesnt do this

laserlight

I still have doubts if EditPad Pro is the problem. Nonetheless, we have a list of code editors used by members of this community. Personally, I use Notepad++.