CREATE TABLE CUSTOMER (Address VARCHAR2, CustomerId VARCHAR2, country VARCHAR2)
CREATE TABLE INVOICE (CustomerId VARCHAR2)

Find the address of all customers that live in Germany and have invoice.
SELECT DISTINCT T1.Address FROM CUSTOMER AS T1 JOIN INVOICE AS T2 ON T1.CustomerId = T2.CustomerId WHERE T1.country = "Germany"
SELECT DISTINCT "T1"."Address" FROM "CUSTOMER" "T1" JOIN "INVOICE" "T2" ON "T1"."CustomerId" = "T2"."CustomerId" WHERE "Germany" = "T1"."country"