There is many way that you can do this. A simple query you can try :-
select x.* from (
select DISTINCT category_skus.sku, products.created_date from category_skus
LEFT JOIN products on category_skus.sku = products.sku
WHERE category_code BETWEEN '70699' and '70791'
union all
select DISTINCT category_skus.sku, products.created_date from category_skus
LEFT JOIN products on category_skus.sku = products.sku
WHERE category_code = '60130' or catagory_code='60420'
)x where x.created_date > "2013-09-13"
OR
select DISTINCT s.sku, p.created_date from category_skus s
LEFT JOIN products p on s.sku = p.sku
WHERE s.category_code BETWEEN '70699' and '70791' or (s.catagory_code='60130' or s.catagory_code='60420') and
p.created_date > "2013-09-13"
Hope it will help you.