[PHP] how to determine if a mysql query returns an empty set?
Is there a way to determine if a mysql query returns an empty set? I am
selecting 10 results at a time with a limit statement and need to know
when i've ran out of rows. I've only got 2 rows in the database, so
when I start with row 10, it returns an empty set. I have the following
code:
//running this query gives Empty set (0.00 sec) in mysql console.
$get_requests = select form_id, full_name, email, phone, division,
location, date_format(time_of_request, '%m-%d-%Y %r') as
time_of_request, contact_time, problem, accepted_by,
date_format(accepted_time, '%m-%d-%Y %r') as accepted_time, resolution,
date_format(resolution_time, '%m-%d-%Y %r') as resolution_time from form
where ((stage = 'Closed') (email = 'awilliam' )) order by
resolution_time limit 10 , 10
//checks to see if it returns nothing, then print that you are at the
end of the results
if (!$mysqli_get_requests =
mysqli_query($mysqli,$get_requests))
{
echo You have reached the end of the results.
Please press the back button.
form action=/helpdesk/login.php method=postinput
type=submit value=Back
name=submit/form/body/html;
exit;
}
but that doesn't work, because I guess an empty set is not false, 0, or
NULL?
Re: [PHP] how to determine if a mysql query returns an empty set?
mysql_num_rows() maybe? if not I probably haven't understood your question.
On Thu, Apr 23, 2009 at 8:12 PM, Adam Williams awill...@mdah.state.ms.uswrote:
Is there a way to determine if a mysql query returns an empty set? I am
selecting 10 results at a time with a limit statement and need to know when
i've ran out of rows. I've only got 2 rows in the database, so when I start
with row 10, it returns an empty set. I have the following code:
//running this query gives Empty set (0.00 sec) in mysql console.
$get_requests = select form_id, full_name, email, phone, division,
location, date_format(time_of_request, '%m-%d-%Y %r') as time_of_request,
contact_time, problem, accepted_by, date_format(accepted_time, '%m-%d-%Y
%r') as accepted_time, resolution, date_format(resolution_time, '%m-%d-%Y
%r') as resolution_time from form where ((stage = 'Closed') (email =
'awilliam' )) order by resolution_time limit 10 , 10
//checks to see if it returns nothing, then print that you are at the end
of the results
if (!$mysqli_get_requests =
mysqli_query($mysqli,$get_requests))
{
echo You have reached the end of the results.
Please press the back button.
form action=/helpdesk/login.php method=postinput
type=submit value=Back
name=submit/form/body/html;
exit;
}
but that doesn't work, because I guess an empty set is not false, 0, or
NULL?
Re: [PHP] how to determine if a mysql query returns an empty set?
On Thu, Apr 23, 2009 at 2:12 PM, Adam Williams
awill...@mdah.state.ms.us wrote:
Is there a way to determine if a mysql query returns an empty set? I am
selecting 10 results at a time with a limit statement and need to know when
i've ran out of rows. I've only got 2 rows in the database, so when I start
with row 10, it returns an empty set. I have the following code:
//running this query gives Empty set (0.00 sec) in mysql console.
$get_requests = select form_id, full_name, email, phone, division,
location, date_format(time_of_request, '%m-%d-%Y %r') as time_of_request,
contact_time, problem, accepted_by, date_format(accepted_time, '%m-%d-%Y
%r') as accepted_time, resolution, date_format(resolution_time, '%m-%d-%Y
%r') as resolution_time from form where ((stage = 'Closed') (email =
'awilliam' )) order by resolution_time limit 10 , 10
//checks to see if it returns nothing, then print that you are at the end of
the results
if (!$mysqli_get_requests =
mysqli_query($mysqli,$get_requests))
{
echo You have reached the end of the results.
Please press the back button.
form action=/helpdesk/login.php method=postinput
type=submit value=Back
name=submit/form/body/html;
exit;
}
but that doesn't work, because I guess an empty set is not false, 0, or
NULL?
It won't be any of those because the query is successful even if it
returns no records. You could use
http://us2.php.net/manual/en/mysqli-stmt.num-rows.php to determine how
many rows were returned.
Andrew
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Re: [PHP] how to determine if a mysql query returns an empty set?
Nitsan Bin-Nun wrote:
mysql_num_rows() maybe? if not I probably haven't understood your question.
Thanks, I never thought of trying that. This code works!
$mysqli_get_requests = mysqli_query($mysqli,$get_requests);
if (!mysqli_num_rows($mysqli_get_requests))
{
echo You have reached the end of the results.
Please press the back button.
form action=/helpdesk/login.php method=postinput
type=submit value=Back
name=submit/form/body/html;
exit;
}
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To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] how to determine if a mysql query returns an empty set?
Andrew Ballard wrote: It won't be any of those because the query is successful even if it returns no records. You could use http://us2.php.net/manual/en/mysqli-stmt.num-rows.php to determine how many rows were returned. Andrew Oh ok, thanks that makes sense. Thanks for the link also -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
