The thing that i need is the, Firstname, Lastname and Email of the customer who purchased the product with reference 1800 and 1898. before 2018-05-18.
I have tried this query:
select pscustomer.firstname, lastname , email from pscustomer inner join psproduct where psproduct.reference in (1800,1898) and psproduct.dateadd >= 2018-05-18
but that gives just all the information of ALL customers back and that's not what i want.
Pleasse help my!