UNION give me warning

daok

Error:

Warning: mysql_fetch_array(): supplied argument is not a valid MySQL result resource in c:\program files\easyphp\www\classCalcul.php on line 198

Code:

$sql = '( SELECT pts_weapons_user, pts_food_users, pts_construction_users, pts_trainer_users 
				FROM users
				WHERE id_users = ' . $user_id . ' ) UNION 
				( SELECT capacite_camp 
				FROM CAMP 
				WHERE id_camp =  ' . $user_id .' )' ;



	$result = mysql_query($sql);
	$row = mysql_fetch_array($result);

The last line is the error.

barand

Could be a couple of reasons

Your version of mysql does not support unions
Your second select should contain the same number of fields of the same type as your first select. Pad it with zeroes or empty strings or nulls.

hth

jkohns

at first glance, I think it's the quotes giving you a problem ...I'd use this:

$sql = "SELECT users.pts_weapons_user, users.pts_food_users, users.pts_construction_users, users.pts_trainer_users, camp.capacite_camp FROM users, camp WHERE users.id_users = camp.id_camp && users.id_users='$user_id'";

daok

jkohns

it work!!! Thx for your code but I dont understand why I have to use double '&' ?

jkohns

&& works the same as AND- just a convetion I prefer- seems clearer when reading through queries to me

daok

But when you take data from 2 tables you shouldn't do a union? If not explain me please when should I use union.

jkohns

Well, what you needed (I think) in this case is actually a JOIN syntax- when you want data from with a common key. A UNION would be where you want ALL the data from one or more tables->

(SELECT FROM table1 WHERE user_id='userA')
UNION
(SELECT FROM table1 WHERE user_id='userB')

would give you all the results for both users

daok

thx 🙂 I understand now