varchar type not equals or not null value : VARCHAR2 « SQL Data Types « Oracle PL/SQL Tutorial

1. Oracle PL/SQL Tutorial
2. SQL Data Types
3. VARCHAR2

SQL>
SQL>
SQL> CREATE TABLE book(
  2    title_id   CHAR(3)      NOT NULL,
  3    title_name VARCHAR(40)  NOT NULL,
  4    type       VARCHAR(10)  NULL    ,
  5    pub_id     CHAR(3)      NOT NULL,
  6    pages      INTEGER      NULL    ,
  7    price      DECIMAL(5,2) NULL    ,
  8    sales      INTEGER      NULL    ,
  9    pubdate    DATE         NULL    ,
 10    contract   SMALLINT     NOT NULL
 11  );

Table created.

SQL>
SQL>
SQL>
SQL>
SQL> INSERT INTO book VALUES('T01','Java','history','P01',111,21.99,566,DATE '2000-08-01',1);

1 row created.

SQL> INSERT INTO book VALUES('T02','Oracle','history','P03', 114,19.95,9566,DATE '1998-04-01',1);

1 row created.

SQL> INSERT INTO book VALUES('T03','SQL','computer','P02', 122,39.95,25667,DATE '2000-09-01',1);

1 row created.

SQL> INSERT INTO book VALUES('T04','C++','psychology','P04', 511,12.99,13001,DATE '1999-05-31',1);

1 row created.

SQL> INSERT INTO book VALUES('T05','Python','psychology','P04', 101,6.95,201440,DATE '2001-01-01',1);

1 row created.

SQL> INSERT INTO book VALUES('T06','JavaScript','biography','P01', 173,19.95,11320,DATE '2000-07-31',1);

1 row created.

SQL> INSERT INTO book VALUES('T07','LINQ','biography','P03', 331,23.95,1500200,DATE '1999-10-01',1);

1 row created.

SQL> INSERT INTO book VALUES('T08','C#','children','P04', 861,10.00,4095,DATE '2001-06-01',1);

1 row created.

SQL> INSERT INTO book VALUES('T09','SQL Server','children','P04', 212,13.95,5000,DATE '2002-05-31',1);

1 row created.

SQL> INSERT INTO book VALUES('T10','AJAX','biography','P01', NULL,NULL,NULL,NULL,0);

1 row created.

SQL> INSERT INTO book VALUES('T11','VB','psychology','P04', 821,7.99,94123,DATE '2000-11-30',1);

1 row created.

SQL> INSERT INTO book VALUES('T12','Office','biography','P01', 507,12.99,100001,DATE '2000-08-31',1);

1 row created.

SQL> INSERT INTO book VALUES('T13','VBA','history','P03', 812,29.99,10467,DATE '1999-05-31',1);

1 row created.

SQL>
SQL>
SQL>
SQL> SELECT title_id, type, pubdate
  2    FROM book
  3    WHERE type = 'biography'
  4      AND pubdate IS NOT NULL;

TIT TYPE       PUBDATE
--- ---------- ---------
T06 biography  31-JUL-00
T07 biography  01-OCT-99
T12 biography  31-AUG-00

SQL>
SQL> drop table book;

Table dropped.

SQL>
SQL>
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