Hi Nitin
Thanks - I tried that and got 0 rows...
I have spent more time on describing my problem -- see below hopefully
this will make the issue more clear...
Rich
<<<<<<<<<<<<<<<<<
I have a MySQL database with a menu table and a product table.
- The products are linked to the menus in a one-to-many relationship
i.e. each product can be linked to more than one menu
- The menus are nested in a parent child relationship
- Some menus may contain no products
The desire is that when a user clicks on a menu entry then all products
linked to that menu - there may be none - will get displayed as well as
all products linked to any child menus of the menu clicked on ...
So say we have a menu like this:-
Motor cycles -> Sports bikes -> Italian -> Ducati
Motor cycles -> Sports bikes -> Italian -> Moto Guzzi
Motor cycles -> Sports bikes -> British -> Triumph
Motor cycles -> Tourers -> British -> Triumph
Motor cycles -> Tourers -> American -> Harley-Davidson
.
etc etc
Clicking on 'Sports bikes' will show all products linked to 'Sports
bikes' itself as well as all products linked to ALL menus below 'Sports
bikes', clicking on 'Harley-Davidson' will just show products for that
entry only.
Below are 'describe table' for the 2 main tables in question NB there is
a 3rd table that holds product descriptions which I won't show as I
don't think it is relevant here:-
CREATE TABLE `menu` (
`menuid` int(11) unsigned NOT NULL AUTO_INCREMENT,
`parent_menuid` int(11) unsigned NOT NULL,
`name` varchar(255) NOT NULL,
PRIMARY KEY (`menuid`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8
CREATE TABLE `menu_product` (
`menuid` int(11) unsigned NOT NULL,
`productid` int(11) unsigned NOT NULL,
PRIMARY KEY (`menuid`,`productid`),
KEY `prodidx` (`productid`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8
For the sake of this question I will simplify it and say there is only 2
levels of nesting i.e. root level and 1 level below that... this is the
query I came up with:-
SELECT DISTINCT
p.productid,
pd.name
FROM menu_product as p
INNER JOIN menu as m ON (m.menuid = p.menuid)
INNER JOIN product_description as pd ON (pd.productid = p.productid)
LEFT JOIN menu as m2 ON (m2.parent_menuid = m.menuid) # User selected
menu may itself be a child menu...
WHERE (m.name = '<name obtained from user's click>' OR p.productid IN
(SELECT p2.productid from menu_product AS p2 WHERE p2.menuid = m2.menuid)
Anyway when I run the above query it returns far too many entries from
menus that are totally unrelated...
I have been staring too hard at this for too long - I am sure it will be
a forehead slapper!
I hope I have explained this sufficiently and I TYIA for any guidance
Rich
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