Query Help on RowNum

Question

Hi ,
Please help me on this…
Select * from EMP where Emp_Type in (1, 2 ) order by Emp_Type;
the above query gives me the result like this
Emp_Id Name Emp_Type
100     asas     1
101 dsds     1
122     gfgf     1
154     ytytyt     1
125     uyuy     1
153     reree     2
154     ytytt     2
600     trtrtr     2
700 gfghf 2
If I pass the Start with num 2 and give 3 as number of records to be displayed. I need to retrieve only the following rows..
Emp_Id Name Emp_Type
101 dsds     1
122     gfgf     1
154     ytytyt     1
154     ytytt     2
600     trtrtr     2
700 gfghf 2
If the Emp_Type was only one ie,
Select * from EMP where Emp_Type in (1) order by Emp_Type;
I know I can get it done by using TOP-N query method
select * from
(Select rownum RWnum ,A.* From
(Select * from EMP where Emp_Type in (1) order by Emp_Type) A
where rownum<=4)
where RWnum>=2;
but I am stuck up with doing for multiple Emp_Type..
here the Emp_Type could be more than two values…
Regards
Ben Narendran

Answer 1

Hi muthukumar S,dnikiforv,Vsugur
Thanks a lot for the analytical function ROW_NUMBER().
But still have some concern about the query you have given..
Let me first run the inner query.
SQL>
SQL > Select e.*,row_number() over(partition by Emp_Type order by Emp_Type) rno from
EMP e where Emp_Type in (1, 2 ) order by Emp_Type;
EMP_ID NAME EMP_TYPE RNO
154 aaa 1 1
101 dsds 1 2
122 gfgf 1 3
125 aaa 1 4
100 asas 1 5
700 gfghf 2 1
600 trtrtr 2 2
153 reree 2 3
If I give the range from 2 and 3 am suppose to get the following rows.
EMP_ID NAME EMP_TYPE RNO
101 dsds 1 2
122 gfgf 1 3
600 trtrtr 2 2
153 reree 2 3
when I run the query you sent am getting the following result..
SQL > select * from
(Select e.*,row_number() over(partition by Emp_Type order by Emp_Type) rno from
EMP e where Emp_Type in (1, 2 ) order by Emp_Type)
where rno between 2 and 3;
EMP_ID NAME EMP_TYPE RNO
101 dsds 1 2
154 aaa 1 3
600 trtrtr 2 2
700 gfghf 2 3
Here the company id 700 is not suppose to come, instead I have to get 153.
So I made some changes in the view and , wrote it like this
SQL> select * from
(select rno Rwnum,Outer_Qry.* from
(select Real_Qry.*,row_number() over(partition by emp_type order by emp_type)rno
from
(select emp_id,name,emp_type from emp where emp_type in (1,2) order by emp_type)Real_Qry)Outer_Qry
where rno <=3)
where Rwnum >=2;
RWNUM EMP_ID NAME EMP_TYPE RNO
2 101 dsds 1 2
3 122 gfgf 1 3
2 600 trtrtr 2 2
3 153 reree 2 3
I guess now am getting the correct result..
Please correct me if I am wrong, and please let me know if I have to make any modification on it..
Thanks and regards
Ben