Illegal String offset in php

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

mysqli_result::fetch_assoc -- mysqli_fetch_assoc — Fetch a result row as an associative array

mysqli_mysqli_fetch_assoc returns ONE single row from the database. As you can see in the result of print_r().

The array contains:

Array ( [productName] => iphone [productDesc] => A product from apple [price] => 5 [image] => test/Group/pic.png )

So when you loop through the array in the first iteration $r will contain a string with value "iphone", second loop "A product from apple" and so on.

In your code you are basically saying "from the STRING iphone give me the character at the position 'productName' ", and as you can guess "productName" is not a valid char position in string.

So you need to iterate every row from the table.

<?php
$db1 = new mysqli('localhost',$user,$pass,$db) or die (" Connection failed  ");
$query="Select productName,productDesc,price,image from product where productID=1";
$query_first=mysqli_query($db1,$query) or die("Query not retrieved");

//print_r($query_second);

echo '<table border="1">';
echo '<tr>

     <td> Product Name</td>
     <td> Product Description</td>
     <td> Price</td>
     <td> Image </td>
</tr> ';


while($r=mysqli_fetch_assoc($query_first)) {

    echo '<tr><td>'.$r['productName'];
    echo '</td><td>'.$r['productDesc'];
    echo '</td><td>'.$r['price'];
    echo '</td><td>'.$r['image'];
    echo '</td></tr>';
}//end foreach
echo"</table>";

?>

If you just want 1 single row then you dont need interation

<?php
$db1 = new mysqli('localhost',$user,$pass,$db) or die (" Connection failed  ");
$query="Select productName,productDesc,price,image from product where productID=1";
$query_first=mysqli_query($db1,$query) or die("Query not retrieved");

//print_r($query_second);

echo '<table border="1">';
echo '<tr>

     <td> Product Name</td>
     <td> Product Description</td>
     <td> Price</td>
     <td> Image </td>
</tr> ';


$r=mysqli_fetch_assoc($query_first);

echo '<tr><td>'.$r['productName'];
echo '</td><td>'.$r['productDesc'];
echo '</td><td>'.$r['price'];
echo '</td><td>'.$r['image'];
echo '</td></tr>';

echo"</table>";

?>

mysqli_fetch_assoc returns a row so you don't need to loop through it with:

foreach($query_second as $r)

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