Question

I have three tables in a mySQL databse as such:

orders: order_sequence_number, contact_id, date_ordered ...

orderdetail: order_sequence_number ...

person: contact_id ...

I am trying to delete all rows across the three tables that have a date_ordered value older than two years, however, the date_ordered field only appears in the orders table but the table has links to the other two via the order_sequence_number and contact_id fields.

So, i’d image a bit like this: …

SELECT * FROM orders WHERE date_ordered BETWEEN X AND Y

Then with that record set

DELETE FROM orderdetail WHERE orderdetail.order_sequence_number IN (THE ABOVE)

Etc for persons table … but having no luck.

Seems to me like some sort of nested subquery but I am having difficulty understanding how to do such a query and cant get my head around the convoluted nature of it…

Any pointers would be very much appreciated.

Answer 1

DELETE FROM orderdetail 
WHERE order_sequence_number IN 
(
    SELECT id 
    FROM orders 
    WHERE date_ordered BETWEEN X AND Y
)