Table Items (SQL)

create table ITEMS (Item_No int, Cost int);
insert into ITEMS values (101, 5000);
insert into ITEMS values (102, NULL);
insert into ITEMS values (103, 4000);
insert into ITEMS values (104, 6000);
insert into ITEMS values (105, NULL);
insert into ITEMS values (106, -1000);
SELECT * from ITEMS;

select * from ITEMS where Cost<0;