How to get last value

Question

Hi i have a senerion in which i want to get the last value :-
CREATE TABLE T1
(NAME VARCHAR2(10), NO NUMBER, NO2 NUMBER);
INSERT INTO T1 VALUES('A',10,20);
INSERT INTO T1 VALUES('C',100,2);
INSERT INTO T1 VALUES('B,124,5);
INSERT INTO T1 VALUES('A',1,400);
INSERT INTO T1 VALUES('B,2,234);
INSERT INTO T1 VALUES('B',2,7);
INSERT INTO T1 VALUES('C',21,12);
INSERT INTO T1 VALUES('A',3,300);
INSERT INTO T1 VALUES('B,55,1);
INSERT INTO T1 VALUES('C',234,1);
INSERT INTO T1 VALUES('B',20,72);
INSERT INTO T1 VALUES('A',200,0);
INSERT INTO T1 VALUES('B',546,32);
INSERT INTO T1 VALUES('C',89,888);
INSERT INTO T1 VALUES('B',485,12);
INSERT INTO T1 VALUES('C',1,77);
INSERT INTO T1 VALUES('B',339,12);
INSERT INTO T1 VALUES('A',0,300);
{\code}
Now for all  A i want the value (order by name,no,no2) i.e value of no2 0
for all b i want 32
and for all c i want 1
i.e last value in order by clause.
i tried this
select name,no,no2,last_value(no2)
over(PARTITION BY  name order by no,no2) nm
from t1
can anyone please help me?
Thanks
Edited by: vinod on Jan 6, 2012 8:58 PM                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       

Answer 1

Hi,
Because of the default windowing, it's simpler to use FIRST_VALUE (with the order reversed) than LAST_VALUE.
For example:
SELECT       name, no, no2
,       FIRST_VALUE (no2) OVER ( PARTITION BY  name
                                   ORDER BY        no     DESC
                       ,            no2     DESC
                     )  AS nm
FROM      t1
ORDER BY  name
,            no
,       no2
;Output:
NAME               NO        NO2         NM
A                   0        300          0
A                   1        400          0
A                   3        300          0
A                  10         20          0
A                 200          0          0
B                   2          7         32
B                  20         72         32
B                 339         12         32
B                 485         12         32
B                 546         32         32
C                   1         77          1
C                  21         12          1
C                  89        888          1
C                 100          2          1
C                 234          1          1It helps if you post the exact output you want.
When you use LAST_VALUE (or FIRST_VALUE) you must use an analytic ORDER BY clause. "First" and "last" simply don't make any sense without some kind of ordering.
When you use an analytic ORDER BY clause, you are always windowing.
If you don't specify a windowing clause, it defauts to RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW. That's a very useful default for most analytic functions (including FIRST_VALUE), but it's not so good for LAST_VALUE, because the value from the current row is always the last one. To use LAST_VALUE, you'd have to do something like this:
SELECT       name, no, no2
,       LAST_VALUE (no2)  OVER ( PARTITION BY  name
                                   ORDER BY        no
                       ,            no2
                       RANGE BETWEEN UNBOUNDED PRECEDING
                             AND      UNBOUNDED FOLLOWING
                     )  AS nm
FROM      t1
ORDER BY  name
,            no
,       no2
vinod wrote:Hi i have a senerion in which i want to get the last value :-
CREATE TABLE T1
(NAME VARCHAR2(10), NO NUMBER, NO2 NUMBER);
INSERT INTO T1 VALUES('A',10,20);
INSERT INTO T1 VALUES('C',100,2);
INSERT INTO T1 VALUES('A',0,300);
{\code}
...When you use curly brackets for the \ tags on this site, the closing tag is exactly the same as the opening tag.  Don't put any kind of slash before the keyword.
Edited by: Frank Kulash on Jan 6, 2012 10:43 AM
Added LAST_VALUE example