[Resolved] if $query = "0" ...?

vaska

i'm not sure how to do this...

i'm trying to create a very simplistic menu system...like a tree basically but far more simple...if a section has no data in it i need to return something like "This section has no files yet"

but...i'm not sure how i check a query to see if it has results...and my efforts aren't working yet...

$query = mysql_query ("SELECT * from table WHERE table_section_id='$row_sec[section_id]' ORDER by date DESC") or die ("Not working!");
$row = mysql_fetch_array($query);

now...i added...

if ($query == 0) echo "This section has no files yet";
else { echo ////all the results here

i get the sections looped out...but when there are no files, it doesn't return the correct info...

any ideas? thanks...vaska

Tyris

you could try

if(!$query)

or I read something about something like:

if(!$isset($query)||empty($query))

worth a try...
doubt I'm right tho🙁

tekky

if (!mysql_num_rows($query))
     echo 'This section has no files yet...';
else
     echo 'All your other data...';

vaska

is this where i would use a recursive statement?

it's two queries...one pulling up the sections...and then the second pulling up the data for each section (using info from the first query of course)...

but...i'd prefer only one query where it checks for each section if results > 0 then print the results...else print something else...

but...the recursive thing is a stretch for me...i'm trying to understand this now...

vaska

DoD

your $query will return the output of mysql_query()

mysql_query is always true unless there is an error i believe... so checking if it is false or 0 is just checking if the query went along without a hitch.

In order to see if nothing was returned:

either,

in your while, use IF to check if $row['name'] is true. (will be false if nothing is returned)

for example:

while blah blah blah {
$check=$row['name'];
}
if (!$check) {echo "Message"; }
$check="";

You will need to clear $check if you intend to repeat this.

Or, do a row count on your query, and if it comes out as 0, do your message.

Tyris

@ tekky... shouldnt it be

if(!mysql_num_rows($query))

so if there are no rows it says no files...

Ok...
Check if there are files... pseudo-code:
if no files: display no "This section has etc"
else: loop through query rows to withdraw data...

ie:
for($i=0;$i<mysql_num_rows($query);$row=mysql_get_row($query)) { print $row . <br>; }

or something... cant quite remember how exactly.... but something like that I think...

edit
o yeah... you'll need $query = myql_query($query); or something before that...

tekky

Originally posted by Tyris
@ tekky... shouldnt it be...

correct, I fixed it, I just woke up 😛 thanks 🙂

vaska

thanks for all this help...this is much more complicated than i thought...

however...it works...but i get strange results...at the beginning of the looping I get the "This section has no files yet" message...???

the code...more information in it this time...i didn't bother editing some things out...so, it's a little hectic...

<? $query = mysql_query ("SELECT * from files,templates WHERE files.fsecid='$row_sec[secid]' AND files.ftemplid=templates.templid ORDER by files.date DESC") or die ("No working!");
$row = mysql_fetch_array($query);

if(!mysql_num_rows($query)) echo "This section has no files yet";
else { echo ...
?>

but...i think i was asking the wrong question, because i realize that if there are not files in a $section...it will still output that listing but it won't indicate (unless a user tries to open the link) that there are no files...

i guess, this is what i'm trying to figure out actually...any help? 😃

thanks for the help...vaska

DoD

Dont know if this will make a difference, but:

if(!mysql_num_rows($query)) echo "This section has no files yet"; 
else { echo ...

should be

if(!mysql_num_rows($query)) { echo "This section has no files yet"; }
else { echo ... }

tekky

Originally posted by DoD
Dont know if this will make a difference, but:
if(!mysql_num_rows($query)) echo "This section has no files yet"; 
else { echo ... 
should be
if(!mysql_num_rows($query)) { echo "This section has no files yet"; }
else { echo ... }
[/B]

I am assuming he knows the else needs a closing bracket }

but the if statement is fine
in PHP
if you do

if ($x == $y)
     echo "x = y";
else
     echo "x != y";

its the same as

if ($x == $y)
{
     echo "x = y";
}
else
{
     echo "x != y";
}

DoD

ok, my mistake. My PHP skills arnt that advance that i know every little working of every function 😛

erm, if you still having your problem, see what mysql_num_rows($query) returns when you have 0 records and when you have records...

since it may return "0" if there are 0 records, which technically is TRUE.

tekky

Originally posted by DoD
ok, my mistake. My PHP skills arnt that advance that i know every little working of every function 😛

erm, if you still having your problem, see what mysql_num_rows($query) returns when you have 0 records and when you have records...

since it may return "0" if there are 0 records, which technically is TRUE.

almost feel like im picking on you now DoD....

"0" != TRUE, anything GREATER than "0" == TRUE using
if ($var) ....

0 would be considered "true" if you did this....
if (0 !== false)

however (better example)

$str1 = "abcd";
$str2 = "";
if (str_len($str1)) { echo "we have a string! -> $str1<br>"; }
else { echo "no string :(<br>"; }
if (str_len($str2)) { echo "we have a string here too! -> $str2"; }
else { echo "no string here either.... *sigh* :(<br>"; }

this should output:

We have a string! -> abcd
no string here either.... sigh 🙁

hope that explains it better DoD

also note: in the above example with "x = y" that IF/ELSE IF/ELSE only allow for 1 line to be used in that manner w/o using {}'s

Some online docs regarding comparisons

Weedpacket

Originally posted by vaska

$row = mysql_fetch_array($query);

if(!mysql_num_rows($query)) echo "This section has no files yet";
?>

[/B]

I'm just a little curious about why you attempt to fetch a row from the query before you look to see if there are any rows to fetch.

Thumbnail of a typical approach of mine (less error trapping and abstraction):

$sql = 'SELECT fields...';
$results=mysql_query($sql);
$results_count=mysql_num_rows($results);
if($results_count==0)
{
  // No results
}
else
{
  for($i=0; $i<$results_count; $i++)
  {
    $row = mysql_fetch_array($results);
    //....etc.
  }
}

And, as a free bonus, you get $i, which you can use to number your rows.

seby

whats wrong with this? i normally do this.

if(mysql_num_rows($query)>=1) 
{
      echo 'something found';
}
else
{
       echo 'nothing found';
}

or: == 0
or: < 0

Ravenous

seby.. There's nothing wrong with the code. It is just more wordy than need be. It's not quick and concise. I would use:

if(mysql_num_rows($query)){
     //do something
     }
else{
     //do nothing
     }

One must also take into to consideration which case is going to happen more often. I usually put that case first and the secondary case in the else statement.

vaska

i did get it working...it ended up being a problem of where i was placing my table rows in the code (and not a php error)...so everybody was right...

very educational little exercise for me (at least)...thanks very much for the helps...

vaska