SQL where exists - mysql

Question

I am trying to get the total amount spent on transactions with a specific product sold during the period below.
SELECT
i.Customer,
SUM(i.GrandTotal)
FROM
transaction i
WHERE EXISTS
(SELECT
1
FROM
transactionline il
INNER JOIN product p
ON p.ProductId = il.ProductId
WHERE i.InvoiceDate >= '2016-09-01 00:00:00'
AND i.InvoiceDate <= '2017-08-31 23:59:59'
AND p.TableProductType = 25)
GROUP BY i.Customer;
My problem is that this query has a result the total amount spent during that period and not only transactions with that product involved
I started of with something like this :
SELECT
i.Customer,
SUM(i.GrandTotal)
FROM
transaction i,transactionline il , product p
WHERE i.InvoiceDate >= '2016-09-01 00:00:00'
AND i.InvoiceDate <= '2017-08-31 23:59:59'
AND p.TableProductType = 25);
But this also took much longer and the final result was wrong (cause of the multiplication caused by the join between transaction and transaction line)

Answer 1

few ways, all solutions using the with following as its data source directly before query, but substitute with your table name
with dat
as
(
select 1 tranid,'N' Tableproducttype,9.00 GrandTotal union all
select 1,'N',11.12 union all
select 1,'N',14.23 union all
select 1,'25',8.88 union all
select 1,'N',7.77 union all
select 1,'Y',6.66 union all
select 2,'N',3.21 union all
select 2,'N',19.13 union all
select 2,'Y',1.23 union all
select 3,'Y',4.31 union all
select 4,'Y',15.43 union all
select 4,'Y',15.12 union all
select 5,'N',14.32)
1.) works using an IN
select tranid,sum(GrandTotal) GrandTotal
from dat
where tranid in (select tranid from dat where TableProductType = '25')
group by tranid
2.) using an exists
select tranid,sum(GrandTotal) GrandTotal
from dat
where exists (select 'x' from dat dat_inner
where dat_inner.TableProductType = '25'
and dat_inner.tranid = dat.tranid)
group by tranid
3.) using having, but could be slow
select tranid,sum(GrandTotal) GrandTotal
from dat
group by tranid
having sum(case when TableProductType = '25' then 1 else 0 end)>0 /* at least one product of type 25 */