counting rows in php with sql

Question

For an application I'm trying to count the total of friends. I want to do this with a function but it isn't returning anything. It tells me this:

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

But I only need one parameter. I think I'm totally wrong.

This is the function:

public function GetTotalOfFriends($user_id){
    $db = new Db();
    $select = "SELECT COUNT FROM friendship WHERE (friendship_recipient_id ='" . $user_id ."' OR friendship_applicant_id = '" . $user_id . "') AND friendship_status = 'accepted'";
    $result = $db->conn->query($select);
    $row = mysqli_query($result);
    $total = $row[0];
    echo $total;

I'm trying to print it out in this way:

$friend = new Friendship;
$numberoffriends = $friend->GetTotalOfFriends($user_id);

<?php echo $numberoffriends; ?>

have a look at php.net/manual/en/mysqli.query.php you need to pass a connection and your query not your result — Robin Webdev
– Robin Webdev, Commented Mar 5, 2014 at 15:39

Community · Accepted Answer · 2023-11-17 20:07:23Z

2

You are mixing up a couple of things. The line $result = $db->conn->query($select); already seems to execute a query, but then you try to bypass your database wrapper by passing that query result again to mysqli_query.

Apart from that, I think your query itself is also wrong. COUNT needs a parameter, indicating a field or value to count. Quite often COUNT(*) is used, but COUNT('x') might be more efficient in some cases. You can also use a specific field name, and COUNT will count the non-null values for you.

The result you got is a mysql_result object, which you need to use to get to the actual data of the query result. The documentation of this object is here and I suggest that you read it thoroughly.

One possible way to do this is using this:

$resultArray = $result->fetch_row();

This will result in the first (and only) row of your query. It is represented as an array, with one value (since your query returns only one column). You can fetch that value like this:

return $resultArray[0];

You could also use any of the other fetch methods if you want your data in a different fashion.

edited Nov 17, 2023 at 20:07

CommunityBot

11 silver badge

answered Mar 5, 2014 at 15:40

GolezTrol

116k19 gold badges186 silver badges215 bronze badges

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

2 Comments

Marnix Verhulst Over a year ago

I edited my code but now he says: Object of class mysqli_result could not be converted to string

GolezTrol Over a year ago

Yes, you need to get the actual data from the result object, but you shouldn't call mysqli_query again, because that is the procedural version of the method that gave you the object in the first place. I've updated my answer with some code, some more explanation and a useful link.

Collectives™ on Stack Overflow

counting rows in php with sql

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related