converting mysql into mysqli check for query

Question

i have a select query. another short if-form checks if this select query returns something or not.

so i have:

$query = "SELECT `a` FROM `b` WHERE c='$c'";
$test = ($query = mysql_query($query)) ? $mysql_num_rows($query) : 0;

so i would like to convert into mysqli but the following code seems to be wrong ($db = mysqli):

$query = "SELECT `a` FROM `b` WHERE c='$c'";
$test = ($query = $db->query($query)) ? $db->num_rows($query) : 0;

when using:

$test = ($query = mysqli_query($query)) ? mysqli_num_rows($query) : 0;

it will echo the error message:

Warning: mysqli_query() expects at least 2 parameters, 1 given...

so if there is someone who would be that friendly and could give me an advise to solve this i really would appreciate. thanks a lot.

`$mysql_num_rows(...)` is a typo, I'm assuming? Variable functions are about as scary as variable variables. — Marc B, Apr 21 '12 at 22:48
possible duplicate of [mysqli\_query expects at least 2 parameters](http://stackoverflow.com/questions/8073278/mysqli-query-expects-at-least-2-parameters) — JasonMArcher, Dec 30 '14 at 18:45

score 1 · Accepted Answer · answered Apr 21 '12 at 23:03

1

mysqli in procedural mode doesn't default to using the last-established connection like the mysql library does. You have to explicitly include the connection each time:

$test = ($query = mysqli_query($conn, $query)) ? mysqli_num_rows($query) : 0;
                               ^^^^^^

As well, for num_rows, it's mysqli_stmt_num_rows($result)

answered Apr 21 '12 at 23:03

Marc B

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using this echos: Warning: mysqli_query() expects parameter 1 to be mysqli, null given // $db = new mysqli("localhost", "my_user", "my_password", "world"); – bonny Apr 21 '12 at 23:08
well, yeah, you have to pass in whatever var you're using for the mysqli connection handle... That'd be whatever was returned from mysqli_connect() – Marc B Apr 21 '12 at 23:09
sorry, i'm having understanding problems. what does that exactly mean? thanks. – bonny Apr 21 '12 at 23:13
okay as i get it, this errormessage will say that $db is not given. but, $db is $db = new mysqli("localhost", "my_user", "my_password", "world") – bonny Apr 21 '12 at 23:36
hmm... i forgot to say that this happens in a function so that i had to set global $db. thanks a lot for helping. – bonny Apr 21 '12 at 23:49
"mysqli in procedural mode doesn't default to using the last-established connection like the mysql library does." It's a pain but an obligation. – Nadjib Mami Dec 05 '12 at 15:44

score 0 · Answer 2 · answered Apr 21 '12 at 23:05

0

If you're using the procedural style (i.e. mysqli_query instead of OO approach), then you should add the $link var to your parameters of the mysqli_query

answered Apr 21 '12 at 23:05

the_red_baron

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converting mysql into mysqli check for query

2 Answers2