MySQL group by URL path pattern - mysql

Question

How to group rows with URLs by path pattern? E.g. we have there addresses:
1 http://example.com
2 http://example.com/products
3 http://example.com/products/some-product
4 http://example.com/categories
5 http://example.com/categories/cat1
6 http://example.com/categories/cat2
7 http://example.com/categories/cat3
8 http://example.com/tags
9 http://example.com/tags/tag1
10 http://example.com/tags/tag2
11 http://example.com/tags/tag3
12 http://example.com/about
So results would be:
1 http://example.com
2 http://example.com/products
3 http://example.com/products/some-product
4 http://example.com/categories
5 http://example.com/categories/cat1
8 http://example.com/tags
9 http://example.com/tags/tag1
12 http://example.com/about
We know domain http://example.com. We need all distinct path types. Basically we want to know what different pages website have. So it's kind of http://example.com/ * / * / * ...

Answer 1

Try this
Rextester Sample
select * from tbl1 t1
where exists
(select 1
from tbl1 t2
group by substring_index(concat(url,'#'),'/',4)
having t1.id=min(t2.id)
);
In MYSQL, there is no hard rule for not selecting columns which are not in group by. So you can go by this as well.
select *
from tbl1
group by
substring_index(concat(url,'#'),'/',4)
order by id
;
Role of substring_index(concat(url,'#'),'/',4)
It will first add an extra character at the end of the url, say #. Then it would truncate the url till the 4th /. Without adding # at the end, http://example.com/categories/cat1 and http://example.com/categories will be put in same group which you dont want.