SQL language

For the following 3 tables: PRODUCT(ID(PK), PNAME) SUPPLIER(SID(PK, SNAME) SUPPLIES(SUID(PFK), PID(PFK)) -- SUID references SUPPLIER's SID, PID references PRODUCT's ID FACTORY(FID(PK), OID(FK)) -- OID references SUPPLIER' SID To get suppliers who are not supplying any products, what goes in the blank? SELECT SNAME FROM SUPPLIER WHERE SID NOT IN