为什么'SELECT count（）'返回'Array'的值？

I am trying to add pagination to my MySQL results page. My goal at the moment is is to divide the number of results in the column ($items_number) by 10 since I want 10 results per page ($per_page = 10).

I had to convert $items into an array since it could not be read as a string, so now I have $items_number = mysqli_fetch_row($items);

When I echo this in my code to see the number of items in a column, I get a message that says:

Notice: Array to string conversion in /home/ikb2014/public_html/test/classic_cars/pag_test.php on line 46

But it also STILL returns a value that says 'Array'. How can I get the value to report the number of items in the column instead of the word 'Array'?

Code:

<?php
require_once("./includes/database_connection.php");

    error_reporting(E_ALL);
    ini_set('display_errors', 1);

    $per_page = 10;
    $query = "SELECT productCode, productName, productLine, productScale, productVendor, productDescription, buyPrice FROM products WHERE `productLine` = 'Classic Cars'";
                $result = mysqli_query($dbc, $query)
                or die(mysqli_error($dbc));

    $query_count = "SELECT count(productLine) FROM products WHERE `productLine` = 'Classic Cars'";
    $items = mysqli_query($dbc, $query_count)
                or die(mysqli_error($dbc));
    $items_number = mysqli_fetch_row($items);


?>

<!DOCTYPE html>
<html>
<head>
    <meta charset='utf-8'>
    <title>Home</title>
    <link type="text/css" rel="stylesheet" href="classic_cars.css" />
</head>

<body>
    <?php
        require_once("./includes/navigation.php");
    ?>


    <?php
        while ($row = mysqli_fetch_array($result)) { 
            $product_code = $row['productCode'];
            $product_name = $row['productName'];
            $product_line = $row['productLine'];
            $product_vendor = $row['productVendor'];
            $product_description = $row['productDescription'];
            $buy_price = $row['buyPrice'];

                echo "<tr>
                <td><p>$product_name</p></td>
                <td><p>$items_number</p></td>
                </tr>";

        } // end while ($row = mysqli_fetch_array($result))

    ?>


    <?php
        require_once("./includes/footer.php");
    ?>      
</body>
</html>

From php documentation:

mysqli_result::fetch_row -- mysqli_fetch_row — Get a result row as an enumerated array
Fetches one row of data from the result set and returns it as an enumerated array, where each column is stored in an array offset starting from 0 (zero)

I will post 2 solutions for your problem: First is to use

mysqli_fetch_row

with COUNT function(like in your code):

$row = mysqli_fetch_row($items);
$items_number = $row[0];

Second is to drop the COUNT FUNCTION and use

mysqli_num_rows

like this

$query_count = "SELECT productLine FROM products WHERE `productLine` = 'Classic Cars'";
$items = mysqli_query($dbc, $query_count)
                or die(mysqli_error($dbc));
$items_number = mysqli_num_rows($items);

I'd do

SELECT count(productLine) as productcount FROM products WHERE `productLine` = 'Classic Cars'

So the key will be productcount in your array. Then

echo "<tr>
                <td><p>$product_name</p></td>
                <td><p>" . $items_number['productcount'] . "</p></td>
                </tr>";

to display it. That number is always going to be the same though, is that what you want?

Oh, also use mysqli_fetch_assoc for that. So $items_number = mysqli_fetch_assoc($items);

I think you in your current implementation

echo "<tr>
                <td><p>$product_name</p></td>
                <td><p>" . $items_number[0] . "</p></td>
                </tr>";

would work. I prefer using assigned names though incase a new column is added to the query or removed. Your 0 will always be the first column.

Links:

http://php.net/manual/en/mysqli-result.fetch-row.php
http://php.net/manual/en/mysqli-result.fetch-assoc.php

Try changing this line

SELECT count(productLine) FROM products WHERE `productLine` = 'Classic Cars'

SELECT count(*) FROM products WHERE `productLine` = 'Classic Cars'