rownum

What is the difference between ROWNUM and ROW_NUMBER ? ROWNUM is a "pseudocolumn" that assigns a number to each row returned by a query: SQL> select rownum, ename, deptno 2 from emp; ROWNUM ENAME DEPTNO ---------- ---------- ---------- 1 SMITH 99 2 ALLEN 30 3 WARD 30 4 JONES 20 5 MARTIN 30 6 BLAKE 30 7 CLARK 10 8 SCOTT 20 9 KING 10 10 TURNER 30 11 FORD 20 12 MILLER 10 ROW_NUMBER is an analytic function that assigns a number to each row according to its ordering within a group of rows: SQL> select ename, deptno, row_number() over (partition by deptno order by ename) rn 2 from emp; ENAME DEPTNO

This question already has an answer here: How ROWNUM works in pagination query? 3 answers When I am using rownum and between keywords then the query doesn't return any rows. Can anyone explain the reason why query is not retrieving any rows? select * from cus where rownum between 2 and 6; I just want to check whether rownum will work when it is used with between keyword .So ,I just tried the above query to display the rows which are in between 2 and 6. But when I tried to execute the query, it doesn't retrieve any rows. thanks in advance Oracle rownum starts at 1, so you will never get the

I hope you can help me with my homework :) We need to build a query that outputs the top N best paid employees. My version works perfectly fine. For example the top 3: SELECT name, salary FROM staff WHERE salary IN ( SELECT * FROM ( SELECT salary FROM staff ORDER BY salary DESC ) WHERE ROWNUM <= 3 ) ORDER BY salary DESC ; Note that this will output employees that are in the top 3 and have the same salary, too. 1: Mike, 4080 2: Steve, 2800 2: Susan, 2800 2: Jack, 2800 3: Chloe, 1400 But now our teacher does not allow us to use ROWNUM . I searched far and wide and didn't find anything useable.

This is a never-ending topic for me and I'm wondering if I might be overlooking something. Essentially I use two types of SQL statements in an application: Regular queries with a "fallback" limit Sorted and paged queries Now, we're talking about some queries against tables with several million records, joined to 5 more tables with several million records. Clearly, we hardly want to fetch all of them, that's why we have the above two methods to limit user queries. Case 1 is really simple. We just add an additional ROWNUM filter: WHERE ... AND ROWNUM < ? That's quite fast, as Oracle's CBO will

This question already has an answer here: How to get second largest or third largest entry from a table 12 answers SELECTing top N rows without ROWNUM? 5 answers I have a employee table in oracle with name,salary and other details. I am trying to get the second highest salary but not able to fetch. This one working fine with e_salary as (select distinct salary from employee) select salary from e_salary order by salary desc And gives output: 450000 61000 60000 50000 40000 30000 20000 6000 but when i am using the same query to fetch second highest row not getting any output select salary from (

I want to populate a table column with a running integer number, so I'm thinking of using ROWNUM. However, I need to populate it based on the order of other columns, something like ORDER BY column1, column2 . That is, unfortunately, not possible since Oracle does not accept the following statement: UPDATE table_a SET sequence_column = rownum ORDER BY column1, column2; Nor the following statement (an attempt to use WITH clause): WITH tmp AS (SELECT * FROM table_a ORDER BY column1, column2) UPDATE tmp SET sequence_column = rownum; So how do I do it using an SQL statement and without resorting to