Empty MySQL query result and displaying...

Mr_Mako

Hi...

I'm in a fix... I'm attempting to run a query on a table in my database, and if the query doesn't find anything, I want a certain $display variable to echo.

However... what's happening is that, if the query doesn't find anything in the table, it doesn't display the $display variable at all.

An example of my code is below:

$find_mission = "SELECT MAX(mission_no) FROM mission";
$find_mission_result = @mysql_query($find_mission, $connect) or die(mysql_error());

while ($row = mysql_fetch_array($find_mission_result)) {
	$mission = $row['MAX(mission_no)'];
}

// Other variables listed below are defined here //

$mis_details_360th = "SELECT * FROM mission WHERE mission_no = '$mission' AND plane_squadron = '360th' ORDER BY plane_name ASC";
$mis_details_360th_result = @mysql_query($mis_details_360th, $connect) or die(mysql_error());

$num_360th_check = mysql_num_rows($mis_details_360th_result);

if($num_360th_check == "0") {
	$display_360th_totals = "
		<tr>
		  <td width=20% bgcolor=#ffffff></td>
		  <td width=10% bgcolor=#ffffff></td>
		  <td width=10% bgcolor=#ffffff></td>
		  <td width=6% bgcolor=#ffffff></td>
		  <td width=6% bgcolor=#ffffff></td>
		  <td width=6% bgcolor=#ffffff></td>
		  <td width=6% bgcolor=#ffffff></td>
		  <td width=6% bgcolor=#ffffff></td>
		  <td width=6% bgcolor=#ffffff></td>
		  <td width=22% bgcolor=#ffffff></td>
		</tr>
		<tr>
		  <td width=100% colspan=10 align=center bgcolor=#EFEFEF><font face=\"Century Gothic\" size=1 color=red><b>360th Squadron on Stand Down for Mission $mission.</b></font></td>
		</tr>";
} else {
	$display_360th_totals = "
		<tr>
		  <td width=20% bgcolor=#ffffff></td>
		  <td width=10% bgcolor=#ffffff></td>
		  <td width=10% bgcolor=#ffffff></td>
		  <td width=6% bgcolor=#ffffff></td>
		  <td width=6% bgcolor=#ffffff></td>
		  <td width=6% bgcolor=#ffffff></td>
		  <td width=6% bgcolor=#ffffff></td>
		  <td width=6% bgcolor=#ffffff></td>
		  <td width=6% bgcolor=#ffffff></td>
		  <td width=22% bgcolor=#ffffff></td>
		</tr>
		<tr>
		  <td width=20% bgcolor=#EFEFEF><font size=1><font face=\"Century Gothic\" color=#800000><center><b>360th Totals</b></center></font></td>
		  <td width=10% bgcolor=#EFEFEF><font size=1><font face=\"Century Gothic\" color=#800000><center>&nbsp;</center></font></td>
		  <td width=10% bgcolor=#EFEFEF><font size=1><font face=\"Century Gothic\" color=#800000><center><b>$tot_360th_perc_rnd%</b></center></font></td>
		  <td width=6% bgcolor=#EFEFEF><font size=1><font face=\"Century Gothic\" color=#800000><center><b>$kill_tot_360th</b></center></font></td>
		  <td width=6% bgcolor=#EFEFEF><font size=1><font face=\"Century Gothic\" color=#800000><center><b>$dmg_tot_360th</b></center></font></td>
		  <td width=6% bgcolor=#EFEFEF><font size=1><font face=\"Century Gothic\" color=#800000><center><b>$kia_360th_tot_count</b></center></font></td>
		  <td width=6% bgcolor=#EFEFEF><font size=1><font face=\"Century Gothic\" color=#800000><center><b>$wia_360th_tot_count</b></center></font></td>
		  <td width=8% bgcolor=#EFEFEF><font size=1><font face=\"Century Gothic\" color=#800000><center><b>$sh_360th_tot_count</b></center></font></td>
		  <td width=6% bgcolor=#EFEFEF><font size=1><font face=\"Century Gothic\" color=#800000><center><b>$pow_360th_tot_count</b></center></font></td>
		  <td width=22% bgcolor=#EFEFEF><font size=1><font face=\"Century Gothic\" color=#800000><center>&nbsp;</center></font></td>
		</tr>";
}

I want the "$display_360th_totals" to either show the results queried from the database, or, if the query doesn't find anything, to display the "360th Squadron on Stand Down" variable.

I created the mysql_num_rows variable ("$num_360th_check") for the express purpose to do this... I've error checked that variable to ensure that it's getting the results I'm looking for.

I'm not sure what I'm doing wrong. Anyone have any ideas?

noimad1

Just to clarify, you mentioned that you error checked the $num_360th_check. Did you do this by actually echo'ing out the $num_360th_check after you assign the number of rows to it?

and when it is equal to 0 it is still not displaying the value you set in the first part of your if statement?

This might be a shot in the dark, but have you tried your if statement without quotes around the "0"?

if ($num_360th_check == 0) {

}

When the value is set to 0, does $display_360th_totals display as blank or still get assigned the info from your else statement?

nemonoman

noimad is right, if no rows, $display_360th_totals == 0, not "0"

better to use:

if($display_360th_totals){/ found some rows /}
else { / result was 0 rows , use bailout routine /}

Mr_Mako

Yes, I always error check by echo'ing variables so I can make sure I'm getting the results I'm looking for.

The error check of $num_360th_check does come out to be 0, but still does not display the $display variable.

I'll run the script when I get home tonight without the quotes and see what happens.

nemonoman

If you echo out variables, then try this:

echo 'test if display_360th_totals == "0" .... '. $display_360th_totals == "0";

echo "<BR>\n"

echo 'test if display_360th_totals == 0 (zero) .... '. $display_360th_totals == 0;

My hypothesis is that this will return:

test if display_360th_totals == "0" .... 0
test if display_360th_totals ==0 .... 1

Remember 0 is not equal to "0"

Mr_Mako

None of the suggestions so far have worked. 🙁

I've removed the quotes from the $display_360th_totals variable, and still the same situation.

In either case, $display_360th_totals still comes up with 0 (no quotes) as the variable's value.

I'm stumped. I've never run across this before... the if/else statement should display SOMETHING... one or the other. I can't figure it out.

nemonoman

Do me a kindness and put insert this code in your program after this line:

$num_360th_check = mysql_num_rows($mis_details_360th_result);

// INSERT STARTS
$x= mysql_error($mis_details_360th_result);
$y= mysql_errno($mis_details_360th_result);
echo "The result code for the query was: $y, $x<BR>";
echo "rows returned was: $num_360th_check <BR>";
if($num_360th_check){ echo "variable has a value";}
else{ echo "variable is false";}

// INSERT ENDS

if($num_360th_check == "0") { //etc... your old code here

DON'T THINK ABOUT IT. JUST RUN THE INSERT CODE!

Mr_Mako

Ok... hehe.

I did... and this is what I get:

Warning: Supplied resource is not a valid MySQL-Link resource in /var/www/html/303rd/360th_test.php on line 28

Warning: Supplied resource is not a valid MySQL-Link resource in /var/www/html/303rd/360th_test.php on line 29
The result code for the query was: , 
rows returned was: 0 
variable is false