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From:Nitin Mehta Date:August 27 2012 5:46am
Subject:Re: Having trouble with SQL query
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I'm more of an hit and try guy and do good only with a data set available. Still I think
making a little change might do the trick.
 
 
SELECT DISTINCT
            p.productid,
            pd.name
FROM menu_product as p
INNER JOIN menu as m ON (m.menuid = p.menuid AND m.name = '<name obtained from user's
click>')
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 p.productid IN (SELECT p2.productid from menu_product AS p2 WHERE p2.menuid =
m2.menuid)


Hope that works.
 
 
Regards,
  

________________________________
 From: rich gray <rich@stripped>
To: mysql@stripped 
Sent: Monday, August 27, 2012 2:46 AM
Subject: Having trouble with SQL query
  
I have a MySQL database with a menu table and a product table linked to the menus *(each
product can be linked to more than menu row)* and the menus are nested.

The query is that when a user clicks on a menu entry then all products linked to that
entry *(there may be none)* will get displayed as well as all products linked to child
menus... below are describe tables for the 2 main tables in question (there is a 3rd
table that holds product descriptions which I won't show as I don't think it is relevant)

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 AUTO_INCREMENT=225 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

Anyway for the sake of this question lets say there is only 2 levels of nesting so a
parent menu can only have children so no grandkids+ 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 the above query returns many 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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Thread
Having trouble with SQL queryrich gray26 Aug
  • Re: Having trouble with SQL queryNitin Mehta27 Aug
    • Re: Having trouble with SQL queryrich gray27 Aug
      • Re: Having trouble with SQL queryShawn Green27 Aug