Problem with if loop

Black_Rider

Hi I'm having a problem writing a script that gets information from a MySQL database and displays it. I am trying to use an if loop to write a script that will take homework from a MySQL database, and display the various pieces of homework. If there is no homework, the script displays 'No Homework'. When I added the if loop and ran the script, with 5 pieces of homework in the database, it only showed the latest piece. I want the script to show all the pieces of homework, and if there is none then show 'No Homework'. The latter part I have done.

CODE:

<?
$dbh=mysql_connect("localhost","ictdoha_sql","sql") or die("I cannot connect");
mysql_select_db("ictdoha_homework") or die("I cannot select a database");
$result=mysql_query("SELECT * FROM 7G_homework ORDER BY date_set desc");
$num_results=mysql_num_rows($result)
?>
<? if($num_results >= 1)
{
$template_rows=mysql_fetch_array($result);
//process the results (if any)
?>

<TABLE cellspacing=3 cellpadding=1 border=0 width="90%" align="left">
<TR>
<TD class=desc valign=top width="15%" bgcolor="#5c5c5c">
<B> Date Set</B>
<BR>
</TD>
<TD class=desc valign=top width="75%" bgcolor="#202029">
 <? echo $template_rows["date_set"]; ?>
<BR>
</TD>
</TR>
<TR>
<TD class=desc valign=top width="15%" bgcolor="#5c5c5c">
<B> Date Due </B>
<BR>
</TD>
<TD class=desc valign=top width="75%" bgcolor="#202029">
 <? echo $template_rows["date_due"]; ?>
<BR>
</TD>
</TR>
<TR>
<TD class=desc valign=top width="15%" bgcolor="#5c5c5c">
<B> What you need to do</B>
<BR>
</TD>
<TD class=desc valign=top width="75%" bgcolor="#202029">
 <? echo $template_rows["homework_desc"]; ?>
</TD>
</TR>
</TABLE>

<BR>
<? $num_results++; } else { ?>
<table align="left" width="90%" cellpadding="0" cellspacing="0" border="0">
<tr>
<td valign="top" align="center" class="staff">NO HOMEWORK
</td>
</tr>
</table>
<BR>
<? } ?>

bad76

Originally posted by Black Rider
Hi ... if loop ...

Hi,
"if" is not a loop. You have to use "while" instead.
It's better you find a good programming book or tutorial to look for difference between a loop command and a if, it's too important.

see you

Weedpacket

PHP's list of control structures and what they do can of course be found here.

Black_Rider

Can someone write me some code that will allow me to use a while loop to get the information (I have written the code with a while loop), and if the table is empty, then display no homework.

tekky

while($row = mysql_fetch_array($result))
{
     if(mysql_num_rows($result) < 1) { echo 'No homework! PARTY!<br>\n'; break; }
     do this;
     and this;
}

that should answer your questions....
Really, get a book or read the online docs 😉

Black_Rider

In your code, tekky, I don't understand what you mean by

do this;
and this;

Also where would I put the code for the table template if there is homework? Finally when I run your code, and there is no homework in the database, it gives me a blank page.

tekky

while($row = mysql_fetch_array($result))
{
     if(mysql_num_rows($result) < 1) { echo 'No homework! PARTY!<br>\n'; break; }
     echo $row['subject']. " class has homework on " .$row['page']. "!<br>\n"; // put your display code for the html here for how you want the homework to be displayed
}

figured "do this; and this;" was self explanatory as "this is the code that is executed if you have homework"

my bad 😉

this will output:

 Math has homework on page 3!
 Social Studies has homework on page 56!

if those classes had homework and thats how the db was setup...

Black_Rider

OK I can get the script to display the homework, however if there is no homework in the database, the while loop will not process. I have modified the code slightly, but the procedure is still the same.

<?
$dbh=mysql_connect("localhost","ictdoha_sql","sql") or die("I cannot connect");
mysql_select_db("ictdoha_homework") or die("I cannot select a database");
$result=mysql_query("SELECT * FROM 7P_homework ORDER BY date_set desc");
$num_results=mysql_num_rows($result);
while ($template_rows=mysql_fetch_array($result)) {
?>
<? if ($num_results < 1) { // whether or not to display 'NO HOMEWORK' ?>
<table align="left" width="90%" cellpadding="0" cellspacing="0" border="0">
<tr>
<td valign="top" align="center" class="staff">NO HOMEWORK
</td>
</tr>
</table>
<BR>
<? break; } ?>

<!-- Begin Homework element -->
<TABLE cellspacing=3 cellpadding=1 border=0 width="90%">
<TR>
<TD class=desc valign=top width="15%" bgcolor="#5c5c5c">
<B>&nbsp;Date Set</B>
<BR>
</TD>
<TD class=desc valign=top width="75%" bgcolor="#202029">
&nbsp;<? echo $template_rows["date_set"]; ?>
<BR>
</TD>
</TR>
<TR>
<TD class=desc valign=top width="15%" bgcolor="#5c5c5c">
<B>&nbsp;Date Due </B>
<BR>
</TD>
<TD class=desc valign=top width="75%" bgcolor="#202029">
&nbsp;<? echo $template_rows["date_due"]; ?>
<BR>
</TD>
</TR>
<TR>
<TD class=desc valign=top width="15%" bgcolor="#5c5c5c">
<B>&nbsp;What you need to do</B>
<BR>
</TD>
<TD class=desc valign=top width="75%" bgcolor="#202029">
&nbsp;<? echo $template_rows["homework_desc"]; ?>
</TD>
</TR>
</TABLE>
<!-- End Homework element -->
<BR>
<? } ?>

Weedpacket

I wouldn't see that working: if there are no records the while() loop wouldn't run at all - and won't see the "No homework" bit inside.

I wouldn't use a while() loop anyway; I'd use an if() branch to decide if there was something to do, and only loop if I had something loop over.

mysql_query(...)
if(mysql_num_rows(...)<1)
{ No homework
}
else
{ while($row=...)
  { do a row.
  }
}

I wouldn't even write it like that.

mysql_query(...)
$row_count = mysql_num_rows(...);
if($row_count==0)
{ No homework
}
else
{ for($i=0; $i<$row_count; $i++)
  { $row = ...
    do a row.
  }
}

Faster, and you know which row you're on.