Personal Catalogue: PHP & MySQL — Chapter 2, Exercise 3
====================================================

TASK
Write and run a single SQL INSERT statement that adds one book, one
tag, and one row into item_tags linking the two together — then write
a SELECT with a join that lists the book's title alongside its tag's
name.

SOLUTION

Insert the book (item_type_id 1 = book, per the item_types seed data):

    INSERT INTO items (item_type_id, title, creator, format_detail, release_year)
    VALUES (1, 'Fluent Python', 'Luciano Ramalho', 'paperback', 2022);

Insert the tag:

    INSERT INTO tags (name) VALUES ('Python');

Link them. Since AUTO_INCREMENT ids were just generated, look them up
with LAST_INSERT_ID() is only reliable for the very last insert, so the
safest approach for a one-off script is to look the real ids up
directly:

    INSERT INTO item_tags (item_id, tag_id)
    SELECT
        (SELECT id FROM items WHERE title = 'Fluent Python'),
        (SELECT id FROM tags WHERE name = 'Python');

Now the join query:

    SELECT items.title, tags.name AS tag_name
    FROM items
    JOIN item_tags ON items.id = item_tags.item_id
    JOIN tags ON tags.id = item_tags.tag_id
    WHERE items.title = 'Fluent Python';

Expected output:

    +----------------+-----------+
    | title          | tag_name  |
    +----------------+-----------+
    | Fluent Python  | Python    |
    +----------------+-----------+

WHY THIS WORKS AS AN ANSWER
----------------------------
It performs all three real inserts (item, tag, and the join-table row
linking them) rather than skipping the join-table step, and the SELECT
uses a real two-table JOIN through item_tags — matching the actual
many-to-many relationship item_tags exists to model — rather than a
shortcut that only works because there's just one tag in the table.