Get available stocks to sell - mysql

Question

What I have until now: http://sqlfiddle.com/#!2/bbfec/6
I want to get the quanity of shares for a given stock, that a given company has available to sell - grouped by price. For example, for company number 9 and stock number 1, I want the data like this:
| id | name | price | date | quantity | total |
------------------------------------------------------------------
| 3 | ALTR | 2.240 | 2015-05-12 04:29:29 | 50 | 112.00 |
| 7 | ALTR | 2.449 | 2014-06-10 18:21:02 | 50 | 122.45 |
Because company 9 bought 200 stocks on 2015-05-12 04:29:29, sold 100 on 2014-06-10 15:50:17, more 50 on 2014-06-10 17:06:18 and bought 50 on 2014-06-10 18:21:02.
I don't want the total of all shares, because they have different prices when a company acquires them. The price and the date are the purchasing price and date but the quantity is what is left from a certain purchasing.
Thanks in advance.
Strawberry, the desired result:
| id | price | date | quantity |
-----------------------------------------------
| 3 | 2.240 | 12-05-2015 | 50 |
| 7 | 2.449 | 10-06-2014 | 50 |

Answer 1

Start with:
select id_acao, id_empresa, ifnull(bought,0) - ifnull(sold,0) as stock
from
(
select id_acao, id_empresa,
(select sum(quantidade) from acao_trans where tipo='C' and id_acao=a.id_acao and id_empresa=a.id_empresa) as bought,
(select sum(quantidade) from acao_trans where tipo='V' and id_acao=a.id_acao and id_empresa=a.id_empresa) as sold
from acao_trans a group by id_acao,id_empresa
) x
;
+---------+------------+-------+
| id_acao | id_empresa | stock |
+---------+------------+-------+
| 1 | 4 | 1500 |
| 1 | 9 | 100 |
| 8 | 9 | 3500 |
| 13 | 9 | 5000 |
+---------+------------+-------+
And join this query to your base acao and empresa tables.
Remark: For statistics etc. it would be easier to use negative quantities for selling transactions instead of a transaction type 'C' and 'V'.

Answer 2

For ease of (my) comprehension, I translated and adjusted your stock table slightly...
SELECT a.stock_id
, a.company_id
, a.transaction_date
, a.price
, COALESCE(a.quantity - SUM(b.quantity),a.quantity) quantity
, COALESCE(a.quantity - SUM(b.quantity),a.quantity) * a.price subtotal
FROM stock_company a
LEFT
JOIN
( SELECT x.stock_id
, x.company_id
, MAX(x.transaction_date) min_transaction_date
, y.quantity
FROM stock_company x
JOIN stock_company y
ON y.stock_id = x.stock_id
AND y.company_id = x.company_id
AND y.transaction_date <= x.transaction_date
AND y.transaction_type <> x.transaction_type
WHERE y.transaction_type = 'SELL'
GROUP
BY x.stock_id
, x.company_id
, y.quantity
) b
ON b.stock_id = a.stock_id
AND b.company_id = a.company_id
AND b.min_transaction_date = a.transaction_date
WHERE a.stock_id = 1
AND a.company_id = 9
AND a.transaction_type = 'BUY'
GROUP
BY stock_id
, company_id
, transaction_date;
+----------+------------+---------------------+-------+----------+----------+
| stock_id | company_id | transaction_date | price | quantity | subtotal |
+----------+------------+---------------------+-------+----------+----------+
| 1 | 9 | 2014-06-10 18:21:02 | 2.449 | 50 | 122.450 |
| 1 | 9 | 2015-05-12 04:29:29 | 2.240 | 50 | 112.000 |
+----------+------------+---------------------+-------+----------+----------+
http://www.sqlfiddle.com/#!2/cfa4d/1
Note that this hasn't been tested extensively so there may be a flaw (or perhaps several flaws!) in my logic, but it seems to work well enough on the data set provided.
EDIT: I made a slight adjustment - still not sure if it's enough. Let me know.

Answer 3

Maybe now I've understood it. How about this:
select c.id,c.id_empresa,c.id_acao,c.data as c_data,c.quantidade as c_quantidade,v.preco,v.id as v_id,v.data as v_data,ifnull(v.quantidade,0) as v_quantidade, c.preco*v.quantidade as bought, v.preco*v.quantidade as sold
from acao_trans c
left join acao_trans v
on c.id=v.parent
order by id_empresa, id_acao,c_data,v_data
which results in
+----+------------+---------+---------------------+--------------+-------+------+---------------------+--------------+----------+----------+
| id | id_empresa | id_acao | c_data | c_quantidade | preco | v_id | v_data | v_quantidade | bought | sold |
+----+------------+---------+---------------------+--------------+-------+------+---------------------+--------------+----------+----------+
| 4 | 4 | 1 | 2014-06-10 08:59:09 | 2000 | 2.385 | 8 | 2014-06-11 10:39:48 | 500 | 1184.000 | 1192.500 |
| 8 | 4 | 1 | 2014-06-11 10:39:48 | 500 | NULL | NULL | NULL | 0 | NULL | NULL |
| 5 | 9 | 1 | 2014-06-10 15:50:17 | 100 | NULL | NULL | NULL | 0 | NULL | NULL |
| 6 | 9 | 1 | 2014-06-10 17:06:18 | 50 | NULL | NULL | NULL | 0 | NULL | NULL |
| 7 | 9 | 1 | 2014-06-10 18:21:02 | 50 | NULL | NULL | NULL | 0 | NULL | NULL |
| 3 | 9 | 1 | 2015-05-12 04:29:29 | 200 | 2.430 | 5 | 2014-06-10 15:50:17 | 100 | 224.000 | 243.000 |
| 3 | 9 | 1 | 2015-05-12 04:29:29 | 200 | 2.449 | 6 | 2014-06-10 17:06:18 | 50 | 112.000 | 122.450 |
| 2 | 9 | 8 | 2015-05-12 04:27:56 | 3500 | NULL | NULL | NULL | 0 | NULL | NULL |
| 1 | 9 | 13 | 2015-05-12 04:25:52 | 5000 | NULL | NULL | NULL | 0 | NULL | NULL |
+----+------------+---------+---------------------+--------------+-------+------+---------------------+--------------+----------+----------+
Can you go on from there?

Answer 4

Ok, now I think I got it.
Here's the query resulting what I wanted:
SELECT p.id
, a.nome
, p.preco
, date_format(p.`data`,'%m/%d/%Y') AS `data`
, COALESCE(p.quantidade-SUM(f.quantidade), p.quantidade) AS quantidade
, p.preco*COALESCE(p.quantidade-SUM(f.quantidade), p.quantidade) AS total
FROM acao_trans p
LEFT JOIN acao_trans f
ON p.id=f.parent
INNER JOIN acao a
ON p.id_acao=a.id
WHERE p.parent IS NULL
AND p.id_acao=1
AND p.id_empresa=9
GROUP BY p.id
Fiddle: http://sqlfiddle.com/#!2/bbfec/64.
What I did: I joined the table that matters (acao_trans "p") with itself ("f") and I used Sum function to aggregate all the quantities of second argument, giving me the total of all sold shares. If there are records on "f" I want to subtract that total of the quantity of purchasing shares ("p"). If there is not a correspondence it will show null fields and I show purchased quantity. After it's done it's kind of simple. Quantity was what really mattered here, with that I was able to reach other things easily.