Null 比较
--Create a Table for test
CREATE TABLE TESTNULL
(
CODE1 VARCHAR2(20),
NAME1 VARCHAR2(40),
DESC1 VARCHAR2(80)
);
--Insert some test records
INSERT INTO TESTNULL(CODE1,NAME1) VALUES('X001','X001NAME');
INSERT INTO TESTNULL(CODE1) VALUES('X002');
SELECT * FROM TESTNULL;
SELECT * FROM TESTNULL WHERE NAME1=NAME1;
SELECT * FROM TESTNULL WHERE (NAME1 IS NULL OR NAME1=NAME1);
--This case also occurs in SQL Server
CREATE TABLE TESTNULL
(
CODE1 VARCHAR2(20),
NAME1 VARCHAR2(40),
DESC1 VARCHAR2(80)
);
--Insert some test records
INSERT INTO TESTNULL(CODE1,NAME1) VALUES('X001','X001NAME');
INSERT INTO TESTNULL(CODE1) VALUES('X002');
SELECT * FROM TESTNULL;
SELECT * FROM TESTNULL WHERE NAME1=NAME1;
SELECT * FROM TESTNULL WHERE (NAME1 IS NULL OR NAME1=NAME1);
--This case also occurs in SQL Server
Code Example:Test Null.rar