SQL>
SQL> CREATE TABLE DEPT (DEPTNO NUMBER(2),DNAME VARCHAR2(14),LOC VARCHAR2(13) );
Table created.
SQL>
SQL> INSERT INTO DEPT VALUES (10, 'ACCOUNTING', 'NEW YORK');
1 row created.
SQL> INSERT INTO DEPT VALUES (20, 'RESEARCH', 'DALLAS');
1 row created.
SQL> INSERT INTO DEPT VALUES (30, 'SALES', 'CHICAGO');
1 row created.
SQL> INSERT INTO DEPT VALUES (40, 'OPERATIONS', 'BOSTON');
1 row created.
SQL>
SQL> insert into dept ( deptno, dname, loc ) values ( 50, 'IT', NULL );
1 row created.
SQL>
SQL>
SQL> select * from dept where loc = NULL;
no rows selected
SQL> select * from dept where loc IS NULL;
DEPTNO DNAME LOC
---------- -------------- -------------
50 IT
SQL> select * from dept where loc IS NOT NULL;
DEPTNO DNAME LOC
---------- -------------- -------------
10 ACCOUNTING NEW YORK
20 RESEARCH DALLAS
30 SALES CHICAGO
40 OPERATIONS BOSTON
4 rows selected.
SQL>
SQL> drop table dept;
Table dropped.
SQL>
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