GET DATA FROM TXT SUM GROUP BY AND SUBTRACT - sql

Question

Trying to get data from txt file which contains buys and sells like in the format below.
I want to group by items and subtract each other.
I made three queries like totalin and totalout and stock but when I subtract out from in, some items are missing which has not been sold.
This is the data table
+------+---------+--------+
| TYPE | ITEM | AMOUNT |
+------+---------+--------+
| BUY | APPLE | 100 |
| BUY | ORANGE | 100 |
| BUY | APPLE | 200 |
| BUY | ORANGE | 200 |
| SELL | APPLE | 50 |
| SELL | APPLE | 50 |
| SELL | ORANGE | 100 |
| SELL | ORANGE | 100 |
| BUY | COCONUT | 50 |
| SELL | BANANE | 30 |
+------+---------+--------+
I want this output
+---------+--------+
| ITEM | AMOUNT |
+---------+--------+
| APPLE | 200 |
| BANANE | -30 |
| COCONUT | 50 |
| ORANGE | 100 |
+---------+--------+
I made 3 queries for the result that i want, but unfortunately I am stuck.
Here is my queries
QUERY 1 TOTAL IN:
SELECT DATA.TYPE, DATA.ITEM, Sum(DATA.AMOUNT) AS TOTALIN
FROM DATA
GROUP BY DATA.TYPE, DATA.ITEM
HAVING (((DATA.TYPE)="BUY"));
QUERY 2 TOTAL OUT:
SELECT DATA.TYPE, DATA.ITEM, Sum(DATA.AMOUNT) AS TOTALOUT
FROM DATA
GROUP BY DATA.TYPE, DATA.ITEM
HAVING (((DATA.TYPE)="SELL"));
QUERY 3 STOCK:
SELECT DATA.ITEM, [BUY]![TOTAL_IN]-[SELL]![TOTAL_OUT] AS STOK
FROM (DATA INNER JOIN BUY ON DATA.ITEM = BUY.ITEM) INNER JOIN SELL ON DATA.ITEM = SELL.ITEM
GROUP BY DATA.ITEM, [BUY]![TOTAL_IN]-[SELL]![TOTAL_OUT];
How can I made a query which shows the rest as stock.
Many thanks.

Answer 1

You can sum in one go like:
SELECT ITEM,
Sum(iif(data.type = "BUY", AMOUNT, -AMOUNT)) AS Stock
FROM DATA
GROUP BY ITEM;

Answer 2

You can think of SELL as -ve and BUY as +ve Amount.
Then the query becomes as follows
select item
,sum(case when type='BUY' then Amount
when type='SELL' then -Amount
end) as Amount
from data_table
group by item

Answer 3

In MsAccess, you can apply an if-logic block using the iif function and run the query in one step as below.
SELECT item,
SUM(iif ([type] = "SELL", (-1 * Amount), Amount)) as amounts
FROM data
GROUP BY item