How can I simplify this hideous query? - mysql

Question

I've gotten to the point with this query where it's become too unwieldy to modify and I'm sure it's also become rather inefficient.
I have a table of items which may have any variable number of properties so these properties are listed in small tables ... item id and property id usually make up the index, and the property tables will have additional information. In essence they're used for filtering a huge number of items to at least the relevant subset.
SELECT * FROM item
INNER JOIN itemwearTable
ON (id=itemwearTable.itemID AND itemwearTable.wearlocID=1)
WHERE item.id IN (
SELECT id FROM item
LEFT JOIN itemalignTable
ON item.id=itemalignTable.itemID
WHERE
itemalignTable.itemID IS NULL OR
(itemalignTable.itemID=item.id AND itemalignTable.alignID=1)
)
AND
item.id IN (
SELECT id FROM item
LEFT JOIN itemgenderTable
ON itemgenderTable.itemID=item.id
WHERE
itemgenderTable.itemID IS NULL OR
(itemgenderTable.itemID=item.id AND itemgenderTable.genderID=1)
)
AND
(item.id IN (
SELECT id FROM item
LEFT JOIN itemgenreTable
ON item.id=itemgenreTable.itemid
WHERE
itemgenreTable.itemid IS NULL OR
(itemgenreTable.itemID=item.id AND itemgenreTable.genreID=1)
)
OR
item.id IN (
SELECT id from item
LEFT JOIN itemclassTable
ON item.id=itemclassTable.itemid
WHERE
itemclassTable.itemid IS NULL OR
(itemclassTable.itemID=item.id AND itemclassTable.classID=1)
))
AND
item.id IN (
SELECT id from item
LEFT JOIN itemlocTable ON
item.id=itemlocTable.itemid
WHERE
itemlocTable.itemid IS NULL OR
(itemlocTable.itemID=item.id AND itemlocTable.locID=1)
)
AND
item.minlvl <= 50
ORDER BY item.sdesc
Note I've used =1 here in many places to replace the php variables that would normally be part of the script generating the query. The problem is that while these items are used to narrow the results, I have another table itemaffTable that has additional data (amount for example) which matches on item.id=itemaffTable.itemID but I can't seem to see how to get that inserted without seriously messing up what's already there.
Any help is appreciated.

Answer 1

I think this should do it:
SELECT DISTINCT i.*, iwt.* FROM item i
INNER JOIN itemwearTable iwt ON i.id=iwt.itemID
LEFT JOIN itemalignTable iat ON i.id = iat.itemID
LEFT JOIN itemgenderTable igt ON i.id = igt.itemID
LEFT JOIN itemgenreTable igrt ON i.id = igrt.itemID
LEFT JOIN itemclassTable ict ON i.id = ict.itemID
LEFT JOIN itemlocTable ilt ON i.id = ilt.itemID
WHERE (iat.itemID IS NULL OR iat.alignID = 1)
AND (igt.itemID IS NULL OR igt.genderID = 1)
AND (igrt.itemID IS NULL OR igrt.genreID = 1)
AND (ict.itemID IS NULL OR ict.classID = 1)
AND (ilt.itemID IS NULL OR ilt.locID = 1)
AND i.minlvl <= 50
AND iwt.wearlocID=1
ORDER BY i.sdesc

Answer 2

Something like this should work.
SELECT item.*, itemwearTable.* FROM item
INNER JOIN itemwearTable
ON (id=itemwearTable.itemID AND itemwearTable.wearlocID=1)
LEFT JOIN itemalignTable
ON item.id=itemalignTable.itemID
LEFT JOIN itemgenderTable
ON itemgenderTable.itemID=item.id
LEFT JOIN itemgenreTable
ON item.id=itemgenreTable.itemid
LEFT JOIN itemclassTable
ON item.id=itemclassTable.itemid
LEFT JOIN itemlocTable
ON item.id=itemlocTable.itemid
WHERE (itemalignTable.itemID IS NULL OR itemalignTable.alignID=1)
AND (itemgenderTable.itemID IS NULL OR itemgenderTable.genderID=1)
AND (itemlocTable.itemid IS NULL OR itemlocTable.locID=1)
AND ((itemgenreTable.itemid IS NULL OR itemgenreTable.genreID=1)
OR (itemclassTable.itemid IS NULL OR itemclassTable.classID=1))
AND item.minlvl <= 50
ORDER BY item.sdesc