Display the alternate row from table

CREATE TABLE mytb (url_id int, url_addr varchar(100));

INSERT INTO mytb VALUES (1, 'www.google.com');

INSERT INTO mytb VALUES (2, 'www.microsoft.com');

INSERT INTO mytb VALUES (3, 'www.apple.com');

INSERT INTO mytb VALUES (4, 'www.google.com');

INSERT INTO mytb VALUES (5, 'www.cnn.com');

INSERT INTO mytb VALUES (6, 'www.apple.com');

Odd number query

SELECT * FROM (

SELECT url_id rn, url_addr

FROM mytb

) temp

WHERE MOD( temp.rn, 2 ) = 1

Even number query

SELECT * FROM (

SELECT url_id rn, url_addr

FROM mytb

) temp

WHERE MOD( temp.rn, 2 ) = 0