Counting quantities using join and nested queries - mysql

Question

I'm attempting to count stock quantities from active sales orders, which are stored in xcart_order_details. I also want to only count stock from orders placed within x days which have a status of processed 'P' or queued 'Q', and also if the stock type matches certain locations; C1 stock, C2 stock, and so on.
This used to be relatively simple in our old xcart database;
SELECT COUNT(`amount`)
FROM `xcart_order_details`
WHERE `productid` IN (
SELECT `productid`
FROM `xcart_products` WHERE `orderid` IN
(SELECT `orderid`
FROM `xcart_orders`
WHERE `date` > ".$date_range."
AND (`status` = 'P'
OR `status` = 'Q'))
AND (LOWER(param01) = 'c1 stock'
OR LOWER(param01) = 'c2 stock'
OR LOWER(param01) = 'g stock'
OR LOWER(param01) = 'stock')
AND `productid` = ".$safe_prodid.")
This query worked. But now our stock locations are stored in another table called xcart_extra_field_values, and must be retrieved where fieldid = 5;
I've tried using a join to get the value field from xcart_extra_field_values where the fieldid = 5, and attempt to do what I'm doing with the query above, but it doesn't work.
SELECT COUNT(`a.amount`)
FROM xcart_order_details a,
xcart_extra_field_values b
WHERE a.productid IN (
SELECT productid
FROM xcart_products WHERE orderid IN
(SELECT orderid
FROM xcart_orders
WHERE date > 1409529600
AND (status = 'P'
OR status = 'Q'))
AND (LOWER(b.value) = 'c1 stock'
OR LOWER(b.value) = 'c2 stock'
OR LOWER(b.value) = 'g stock'
OR LOWER(b.value) = 'stock')
AND (a.productid = b.productid)
AND (a.productid = 4169)
AND (b.fieldid = 5)
Unfortunately this query does not work, and I know it's a syntax issue, but the error I'm getting is no help whatsoever.
Can anyone shed any light on what I'm doing wrong?

Answer 1

You are missing the criteria how to join the two tables. Let's assume there is an xcart_order_details_id in table xcart_extra_field_values, then use that.
After all, you don't even have to join. You want results from xcart_order_details for which certain detail value records EXIST:
SELECT COUNT(`amount`)
FROM `xcart_order_details`
WHERE `productid` IN
(
SELECT `productid`
FROM `xcart_products`
WHERE `orderid` IN
(
SELECT `orderid`
FROM `xcart_orders`
WHERE `date` > ".$date_range."
AND `status` IN ('P','Q')
)
AND `productid` = ".$safe_prodid."
AND EXISTS
(
SELECT *
FROM xcart_extra_field_values v
WHERE v.xcart_order_details_id = xcart_order_details.id
AND fieldid = 5
AND LOWER(param01) IN ('c1 stock','c2 stock','g stock','stock')
);
BTW: You count how many order detail records have an amount?

Answer 2

Resolved.
SELECT COUNT(a.amount)
FROM xcart_order_details a,
xcart_extra_field_values b
WHERE a.productid IN
(SELECT productid
FROM xcart_products
WHERE orderid IN
(SELECT orderid
FROM xcart_orders
WHERE date > 1409529600
AND (status = 'P'
OR status = 'Q'))
AND (LOWER(b.value) = 'c1 stock'
OR LOWER(b.value) = 'c2 stock'
OR LOWER(b.value) = 'g stock'
OR LOWER(b.value) = 'stock'))
AND (a.productid = b.productid)
AND (a.productid = 4169)
AND (b.fieldid = 5)
Firstly, I was missing a bracket at the end of my query as I was nesting two IN queries, and I needed to remove the Grave accents around a.amount within COUNT, which it didn't like. I only noticed the missing bracket when I looked at my queries side by side.
Edit: Moved my join outside of my nested IN clause, as it made no sense to have it nested.