MySQL Count based on conditions

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Hi There,

Hi all, I have a category structure and I need to count the category levels based on the parent_id.

For example:

cname ¦cid ¦ category_parent_id
cat 1 ¦ 1 ¦ 0
cat 2 ¦ 2 ¦ 0
cat 3 ¦ 3 ¦ 1
cat 4 ¦ 4 ¦ 1
cat 5 ¦ 5 ¦ 3
cat 6 ¦ 6 ¦ 3
cat 7 ¦ 7 ¦ 4
cat 8 ¦ 8 ¦ 0
cat 9 ¦ 9 ¦ 8
cat 10 ¦ 10 ¦ 8
cat 11 ¦ 11 ¦ 0
cat 12 ¦ 12 ¦ 11
cat 13 ¦ 13 ¦ 11
cat 14 ¦ 14 ¦ 0

I need to count cat 6 has a category_parent_id of 3 and cat 3 has a category_parent_id of 1 so this should count 3 times making it 3 levels deep.

I cant work out how to count the repeated occurrences of a category based on it's parent.

Thanks for any advice.

Posted 26-Mar-12 4:17am

Paul Hayman

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wizardzz 26-Mar-12 11:30am

Not sure what you are stuck on? What do you meant by count? It doesn't seem to be the right term here.

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Fredrik Bornander · Answer 1 · 2012-03-26T06:02:00

Recursive selects are your friend here;

SQL

with t as
(
	select * from testtbl as t1
	union all
	select t2.* from testtbl as t2
	join t on t.cid=t2.category_parent_id
)
select cname, count(1) as depth from t
group by cname

I haven't got access to a MySql instance here so I've only tested that on SQLServer.

Hope this helps,
Fredrik

Actually, ignore of all that. MySQL doens't support it I think :(