php mysql_query returns empty value

Question

I created a directory listing and came across this issue.

What value does mysql_query($query1) return if there is no value?

My script received this message from $result, would it be alright to pass array(0)?

Warning: mysql_fetch_array($result) expects parameter 1 to be resource, array given in

possible duplicate of Warning: mysql_fetch_* expects parameter 1 to be resource, boolean given error — John Conde
– John Conde, Commented Jul 29, 2012 at 17:38

rook · Accepted Answer · 2010-05-16 08:19:41Z

3

try:

mysql_query($query1) or die(mysql_error());

answered May 16, 2010 at 8:19

rook

67.1k38 gold badges171 silver badges248 bronze badges

Sign up to request clarification or add additional context in comments.

5 Comments

nico Over a year ago

of course, that's some rough way to check the result of mysql_query. Better to show a meaningful error so that the user knows what happened. Also, the problem is not mysql_query failing (e.g. if the query is not well formed) but mysql_fetch_array failing because there are no results. In that case mysql_num_rows does the job, as @nc3b pointed out

rook Over a year ago

@nico actually displaying the results of a mysql error is a information leakage vulnerability because it allows hackers to better identify sql injection flaws in your system. However i posted it because its easy and to the point.

nico Over a year ago

Rook: Sorry you may have misinterpreted what I was saying. I was suggesting: if (!mysql_query($query)) echo "Doh!!! I couldn't read the DB!! Click here to go back somewhere" :) I just don't like to put die(); like that because the user will be stuck with a blank page not knowing what happened

rook Over a year ago

@nico you could log the repose in a flat file.

nico Over a year ago

Rook: Yeah, that's also another option. Depends on the situation, really. Do the users of your website want to fiddle around with flat files when an error occurs? Probably not (probably they can't either)

nc3b · Accepted Answer · 2010-05-16 08:21:21Z

2

php.net

For SELECT, SHOW, DESCRIBE, EXPLAIN and other statements returning resultset, mysql_query() returns a resource on success, or FALSE on error

If it doesn't return FALSE, you can use mysql_num_rows to find out just how many rows were returned.

answered May 16, 2010 at 8:21

nc3b

16.4k5 gold badges53 silver badges63 bronze badges

Collectives™ on Stack Overflow

php mysql_query returns empty value

2 Answers 2

5 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

5 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related