On 1/16/2012 4:14 PM, bruce wrote:
hi Peter.
Sorry.. Been looking at this for awhile.
In the sample data/tbl I provided, it has two top level root/parents.
Ie, I have two entries that don't have a
parentID. I use 0 to be null.
Mistake. use Null.
The items are (0,1), and (0,8).
Then the table has two trees. See "Multiple trees in one table" at
http://www.artfulsoftware.com/infotree/queries.php.
PB
-----
The (0,1) item, has a number of descendants. The (0,8) only has a
single descendant. For my app, I'm going to have a number of top level
items, and they're each going to have a number of descendants, where I
don't know the number of descendant rows, or the number of actual
descendants.
But either way, once I get the descendant list, I still need some way
of linking the childID of the descendant to the linked ID of the
statusTBL so I can get the status of the childID/app.
And like I said, I'm not quite sure how to proceed in an efficient
manner on this.
Thanks
On Mon, Jan 16, 2012 at 4:08 PM, Peter Brawley
<peter.braw...@earthlink.net> wrote:
On 1/16/2012 2:08 PM, bruce wrote:
Hi Peter.
Not a mysql guru... so I've never used stored procedures/sub-queries..
But it sort of makes sense.
What I'm really trying to get is to be able to take a test table like
below
LOCK TABLES `parentChildTBL` WRITE;
/*!40000 ALTER TABLE `parentChildTBL` DISABLE KEYS */;
INSERT INTO `parentChildTBL` VALUES
(0,1,1),
(1,2,2),
(1,3,3),
(1,4,4),
(2,5,5),
(2,6,6),
(2,7,7),
(0,8,8),
(8,9,9);
UNLOCK TABLES;
and to be able to generate the child/descendant list of the top two/2
items (1,8)
I don't understand "top two(1,8)". In general a non-procedural query of n
recursion levels requires n-1 joins. If the number of recursive references
is unknown beforehand, the only way to query the tree is via a stored
procedure.
PB
----- if I only have a single top level item.. and can do a left join.. but
I'm not sure how to accomplish this with two top items, unless I take a look
at the approach you provided. I'm looking at being able to compare a
'status' from a linked tbl, that links on the childID... thanks On Mon, Jan
16, 2012 at 2:33 PM, Peter Brawley<peter.braw...@earthlink.net> wrote:
On 1/16/2012 12:53 PM, bruce wrote:
On Mon, Jan 16, 2012 at 1:52 PM, bruce<badoug...@gmail.com> wrote:
Hey Authur.
Should have been more clear. I've looked over a number of sites. And
with the exception of the the articles that talk about using the
"Nested List" approach, nowhere did I find data on how to get a
complete list of the child descendants of a given 'root'/top item from
the parent/child TBL.
Look again, eg listings 7 through 7d in
http://www.artfulsoftware.com/mysqlbook/sampler/mysqled1ch20.html.
PB
-----
Chunks of code/pointers would be seriously useful.
Thanks
On Mon, Jan 16, 2012 at 12:18 PM, Arthur
Fuller<fuller.art...@gmail.com>
wrote:
See the piece on trees at www.artfulsoftware.com. It goes into several
variations of how to handle hierarchies.
HTH,
--
Arthur
Cell: 647.710.1314
Prediction is difficult, especially of the future.
-- Neils Bohr
--
MySQL General Mailing List
For list archives: http://lists.mysql.com/mysql
To unsubscribe: http://lists.mysql.com/mysql
