MS-Access SQL loops - sql

Question

I would like to apply a for loop in this sql statement in ms-access something like:
for(i=0;i<8;i++)
{
UPDATE current_stock SET current_stock.quantity = DLookup("quantity","current_stock","stock_id=i")-DLookup("req_quantity","Bom_dell","lap_id=(SELECT lap_id FROM laptop_info WHERE model_name='Dell Inspiron')" And "stock_id=i")
WHERE stock_id=1;
}
Please advise if there is any method in MS-access to be able to do something similar to a for loop using sql queries.
Bom_dell
bom_id lap_id stock_id req_quantity
1 1 1 1
2 1 2 3
3 1 3 6
4 1 4 1
5 1 5 1
6 1 6 2
7 2 7 7
8 2 8 8
9 2 9 1
10 2 10 1
11 2 11 1
12 2 12 3
current_stock
ID lap_id stock_id quantity
1 1 1 11
2 1 2 11
3 1 3 11
lap_info
lap_id model_name model_num price
1 Dell Inspiron INS81 35000
2 Dell XLS XL91 24000
Sample query
UPDATE (SELECT laptop_info.model_name, current_stock.stock_id, Bom_dell.req_quantity, current_stock.quantity
FROM (current_stock INNER JOIN laptop_info ON current_stock.lap_id = laptop_info.lap_id) INNER JOIN Bom_dell ON current_stock.stock_id = Bom_dell.stock_id)
SET quantity=quantity-req_quantity
WHERE stock_id BETWEEN 1 AND 3
AND model_name='Dell Inspiron'
UPDATE (SELECT laptop_info.model_name, current_stock.stock_id, Bom_dell.req_quantity, current_stock.quantity
FROM (current_stock INNER JOIN laptop_info ON current_stock.lap_id = laptop_info.lap_id) INNER JOIN Bom_dell ON current_stock.stock_id = Bom_dell.stock_id) SET quantity = quantity-req_quantity
WHERE stock_id BETWEEN 1 AND 3
AND model_name IN ([Forms]![Invoice1]![laptop_id])

Answer 1

You seem to be looking for something on the lines of:
UPDATE (current_stock
INNER JOIN laptop_info ON laptop_info.stock_id=current_stock.stock_id)
INNER JOIN Bom_dell ON Bom_dell.lap_id = laptop_info.lap_id
SET current_stock.quantity = current_stock.quantity - Bom_dell.req_quantity
WHERE stock_id Between 1 And 8
AND model_name='Dell Inspiron'
Try this. I have used aliases - a is for the current_stock table and b is for the sub query. This assumes that you have one line per stock id in bom_dell.
UPDATE current_stock AS a
INNER JOIN (
SELECT bom_dell.stock_id, lap_info.model_name, bom_dell.req_quantity
FROM bom_dell
INNER JOIN lap_info ON bom_dell.lap_id = lap_info.lap_id
WHERE (((bom_dell.stock_id) Between 1 And 3)
AND ((lap_info.model_name)="Dell Inspiron"))) AS b
ON a.Stock_id = b.Stock_id SET a.quantity = [a].[quantity]+[b].[req_quantity];