Hey folks, I’m trying to change my SQL table structure and could use some help. Right now I’ve got a table that looks like this:
| item_id | category |
|---------|----------|
| 123456 | Widget |
| 789012 | Widget |
| 345678 | Box |
What I want to do is create a new table that shows relationships between the Widgets and the Box. It should look something like this:
| widget_id | box_id |
|-----------|--------|
| 123456 | 345678 |
| 789012 | 345678 |
Basically, I need to link all the Widget items to the Box item. I’m not sure how to go about this in SQL. Any ideas on how to make this work? Thanks in advance for your help!
hmm, interesting challenge! have u considered using a CROSS JOIN? it could be a neat way to link all widgets to the box. what if u tried something like:
SELECT w.item_id AS widget_id, b.item_id AS box_id
FROM items w
CROSS JOIN items b
WHERE w.category = ‘Widget’ AND b.category = ‘Box’;
what do u think? might this work for ur setup?
To achieve the desired transformation, you can create a new relationship table and then populate it using a query that links widget items to their corresponding box.
First, create a table with widget_id and box_id columns. Then, insert data into this table with an INSERT INTO … SELECT statement. For example, you might run:
INSERT INTO widget_box_relationship (widget_id, box_id)
SELECT w.item_id AS widget_id, b.item_id AS box_id
FROM items w
CROSS JOIN (SELECT item_id FROM items WHERE category = 'Box') b
WHERE w.category = 'Widget';
This query assumes a single box entry. If multiple boxes exist, consider adjusting the selection criteria or using additional filtering. Indexing the new table can also help maintain performance.
yo, i think u can do this with a simple INSERT statement. create ur new table first, then do smthin like:
INSERT INTO widget_box (widget_id, box_id)
SELECT w.item_id, b.item_id
FROM items w, items b
WHERE w.category = ‘Widget’ AND b.category = ‘Box’;
this should link all widgets to the box. hope it helps!