Question

I think the title is quite straightforward but basically I have 2 mysql tables that hold various information. Linking them together is a unique id.

One of the tables is showing a total of 2 rows less than the other. I would like to run through these rows and find out which id values are missing. I do not know enough of mysql to say that this is not possible using only mysql but i thought it would be an easier task with php.

so something like this which really is a thumbsuck :

if ($stmt = $link->prepare("
    SELECT i.id AS itemsId, c.item_id AS catsId
    FROM items i
    INNER JOIN item_categories c
    WHERE i.id = c.item_id
"))
{
    $stmt->execute();
    $stmt->bind_result($id1, $id2);
    $stmt->close();
}
while ($stmt->fetch())
{
    *run through the numbers and echo which numbers are missing out of 1 to 300.*
}

Would anyone have any idea on how i could accomplish something like this?

Any advice, suggestion or information would be greatly appreciated, thank you!

Answer 1

SELECT id FROM items WHERE id NOT IN (SELECT item_id FROM item_categories);