Alternatives to LIMIT and OFFSET for paging in Ora

Question

I'm developing a web application and need to page ordered results. I normaly use LIMIT/OFFSET for this purpose.

Which is the best way to page ordered results in Oracle? I've seen some samples using rownum and subqueries. Is that the way? Could you give me a sample for translating this SQL to Oracle:

SELECT fieldA,fieldB 
FROM table 
ORDER BY fieldA 
OFFSET 5 LIMIT 14

(I'm using Oracle 10g, for what it's worth)

Thanks!

---

Answer: Using the link provided below by karim79, this SQL would look like:

SELECT * FROM (
    SELECT rownum rnum, a.* 
    FROM(
        SELECT fieldA,fieldB 
        FROM table 
        ORDER BY fieldA 
    ) a 
    WHERE rownum <=5+14
)
WHERE rnum >=5

Answer 1

You will need to use the rownum pseudocolumn to limit results. See here:

http://www.oracle.com/technology/oramag/oracle/06-sep/o56asktom.html

http://www.oracle.com/technetwork/issue-archive/2006/06-sep/o56asktom-086197.html

Answer 2

Method-1: For database version Oracle12c or higher

SELECT fieldA, fieldB 
FROM table 
ORDER BY fieldA 
OFFSET 5 ROWS FETCH NEXT 14 ROWS ONLY

Method-2: For database version Oracle11g or lower using analytical function RowNumber()

SELECT fieldA, fieldB
FROM (
    SELECT fieldA, fieldB,
        row_number() over (order by fieldA) rowRank
    FROM table_name
)
WHERE rowRank BETWEEN 5 AND 14;

Method-3: For database version Oracle11g or lower using RowNum

SELECT T.* FROM ( 
SELECT T.*, rowNum as rowIndex
FROM (
    SELECT fieldA, fieldB,
    FROM table_name
)T)T
WHERE rowIndex > 0 AND rowIndex <= 20;

In some cases, I have found method-3 is faster than method-2 since order by clause is mandatory in method 2. However, if your database version is 12c or higher you must go for method-1.

Answer 3

As of oracle 12c, you could use the top N queries.

SELECT fieldA,fieldB 
FROM table 
ORDER BY fieldA 
OFFSET 5 ROWS FETCH NEXT 14 ROWS ONLY;

http://www.oracle-base.com/articles/12c/row-limiting-clause-for-top-n-queries-12cr1.php

Answer 4

Since you're on 10g, you should be able to simplify the ROWNUM approach using analytic functions

SELECT fieldA, 
       fieldB
  FROM (SELECT fieldA,
               fieldB,
               row_number() over (order by fieldA) rnk
          FROM table_name)
 WHERE rnk BETWEEN 5 AND 14;