SQL & PL/SQL

Hi experts,

 

CREATE TABLE T ( ID NUMBER,COL1 DATE,COL2 DATE,COL3 DATE)

INSERT INTO T VALUES (1,SYSDATE,SYSDATE-1,SYSDATE-2);
INSERT INTO T VALUES (2,SYSDATE,SYSDATE-2,SYSDATE-3);
INSERT INTO T VALUES (3,SYSDATE,SYSDATE-1,SYSDATE-4);
INSERT INTO T  VALUES (4,SYSDATE,SYSDATE-5,SYSDATE-2);
INSERT INTO T  VALUES (5,SYSDATE-6,SYSDATE-5,SYSDATE-2);
INSERT INTO T  VALUES (6,SYSDATE-6,SYSDATE-5,'');


SELECT * FROM T;

my result should be:

ID MINVALUE
1  1/8/2012 10:14:05 AM
2  1/7/2012 10:14:05 AM
3  1/6/2012 10:14:05 AM
4  1/5/2012 10:14:05 AM
5  1/4/2012 10:15:28 AM
6  1/4/2012 10:35:08 AM

I tried this 

SELECT id,min(col1,col2,col3) minvalue FROM T

but not working

Thanks in advance

Edited by: 846773 on Jan 10, 2012 10:18 AM

Edited by: 846773 on Jan 10, 2012 10:34 AM