[RESOLVED] MySQL functions inside user defined PHP function

nielseno

Why does this work:

$query "SELECT * FROM TABLE";
$result = mysql_query($query,$dbc) or die(mysql_error()) ;
// Print first column of query result 
do {
     echo "<br>";
     echo $row_result[mysql_field_name($result, 0)];
   }
while ($row_result = mysql_fetch_assoc($result));

And this doesn't:

function print_result($result)
{
	do {
				echo "<br>";
				echo $row_result[mysql_field_name($result, 0)];
	   }    

	while ($row_result = mysql_fetch_assoc($result));
}
$query "SELECT * FROM TABLE";
$query_result = mysql_query($query,$dbc) or die(mysql_error()) ;
print_result($query_result);

I've been able to get some MySQL functions to work on the passed query result or resource but others like this do not seem to work. Like echo-ing the $result will show the same resource id inside and outside of the function. I've been able to get the field names via mysql_field_name but printing out the query in the form of a table gives me empty results.

Weedpacket

function print_result($result)
{
    do {
                echo "<br>";
                echo $row_result[mysql_field_name($result, 0)];
       }    

    while ($row_result = mysql_fetch_assoc($result));
}

$row_result is not defined anywhere in this function.

sneakyimp

Well he does define $row_result, but only after the first iteration of his loop. This line will result in a couple of NOTICES/WARNINGS the first iteration:

echo $row_result[mysql_field_name($result, 0)];

It does look like a pretty silly function to me. It seems much easier to use [man]mysql_fetch_array[/man] than using mysql_fetch_assoc and mysql_field_name and then never using the associative key at all.

nielseno

It works in the first regardless without warning or error.

I'll try mysql_fetch_array.

bradgrafelman

nielseno;10999707 wrote:
It works in the first regardless without warning or error.

Only if you don't have errors enabled. 😉 Do you have display_errors set to On and error_reporting set to E_ALL (or better)?

$row_result is undefined for the first iteration of the loop since that loop should probably be a while() loop rather than a do-while() loop.

EDIT: Regardless, I agree with sneakyimp above... it seems silly to fetch an associative array when you don't care about the associative indexes and would rather use numerical indexes.

sneakyimp

You shouldn't have a do/while loop, you should have a while loop.

It's incorrect to refer to a member of the array $row_result before you have bothered to define it. The fact that you don't see any errors suggests that
a) you have your [man]error_reporting[/man] turned down or off
OR
b) display_errors is off or your PHP setup is configured not to show any errors in the browser. perhaps it's writing them to a file.

Not really sure why the function doesn't work and the other item does. You probably need to be more specific about what "doesn't work" means.

nielseno

So, same result. When not in the function it prints out the first column of data. Inside the function, nothing. No errors output on the php page.

// This outputs the same Resource id inside or outside the function.
echo $result;
// This only outputs the first column of data when outside the function
while ($row = mysql_fetch_array($result)) {
    echo "<br>";
    echo $row[mysql_field_name($result, 0)];

bradgrafelman

See my previous question:

bradgrafelman;10999710 wrote:
Do you have display_errors set to On and error_reporting set to E_ALL (or better)?

sneakyimp

I bet there's a syntax error because of a missing semicolon when you define the function.

nielseno

sneakyimp;10999713 wrote:
You shouldn't have a do/while loop, you should have a while loop.

It's incorrect to refer to a member of the array $row_result before you have bothered to define it.

I have tried defining it beforehand with the same results.

sneakyimp;10999713 wrote:
The fact that you don't see any errors suggests that
a) you have your [man]error_reporting[/man] turned down or off
OR
b) display_errors is off or your PHP setup is configured not to show any errors in the browser. perhaps it's writing them to a file.

Not sure here, I do get errors with other mistakes in my code. I will agree that the do/while looks bad, don't know enough to say if it's wrong. I believe I took the code from a Dreamweaver autocode (or whatever you would call it, code generation)

sneakyimp;10999713 wrote:
Not really sure why the function doesn't work and the other item does. You probably need to be more specific about what "doesn't work" means.

Let me know if the comments in my last code are enough to explain how it doesn't work.

nielseno

bradgrafelman;10999720 wrote:
See my previous question:

Sorry for missing your question...

display_errors is On and On (local and master respectively)

sneakyimp

So, same result. When not in the function it prints out the first column of data. Inside the function, nothing. No errors output on the php page.

That's still not very clear. If you are viewing the page in a browser and there is no HTML output at all, this suggests that you have a syntax error in your page and you have error reporting off.

Not sure here, I do get errors with other mistakes in my code.

There are different levels of error in php: E_ERROR, E_NOTICE, E_WARNING. When you refer to an array element for $row result before even defining it, then you should get an E_NOTICE error -- unless you have your error reporting turned down or off. Calling mysql_field_name on a non-existent resource results in E_WARNING. You should read the docs on [man]error_reporting[/man] to learn more. Turning off errors means that you are more likely to write code which works only part of the time because you are not kept apprised of problems in your code.

Haha i found the problem. Your error reporting is definitely turned off I think.

nielseno

sneakyimp;10999722 wrote:
I bet there's a syntax error because of a missing semicolon when you define the function.

Here is the exact regular and function code copied from the script respectivly:

echo $result;
$row = mysql_fetch_array($result);
while ($row = mysql_fetch_array($result)) {
    echo "<br>";
    echo $row[mysql_field_name($result, 0)];
}

function query_function($result)
{
echo $result;
$row = mysql_fetch_array($result);
while ($row = mysql_fetch_array($result)) {
    echo "<br>";
    echo $row[mysql_field_name($result, 0)];
}
}

nielseno

This is the output:

Resource id #16
11
9
11
11
5
9
12
10
11
9
9
12
11
11
9
11
10
9
13
9
10
8
6
8
11
7
10Resource id #16

bradgrafelman

Are you trying to use both versions at once? If so, whichever one is first is going to consume all of the data.

By the time you try the second, the internal result pointer is going to be at the end of the result set (since you just looped through all of the results), thus there won't be any data to loop over.

sneakyimp

So you have it working then?

nielseno

bradgrafelman;10999738 wrote:
Are you trying to use both versions at once? If so, whichever one is first is going to consume all of the data.

By the time you try the second, the internal result pointer is going to be at the end of the result set (since you just looped through all of the results), thus there won't be any data to loop over.

You got it. I can't reuse? I thought I've done that before...

So I couldn't call that function several times in a roq with the same $result?

bradgrafelman

You can reuse a result set, but only after you call [man]mysql_data_seek/man to move the internal pointer back to the beginning of the set.

nielseno

Sneaky, error_reporting was not set. Thanks for the info.

Thanks guys!