How do I limit the number of rows returned by an Oracle query after ordering?

Question

Is there a way to make an Oracle query behave like it contains a MySQL limit clause?

In MySQL, I can do this:

Answer 1

Starting from Oracle 12c R1 (12.1), there is a row limiting clause. It does not use familiar LIMIT syntax, but it can do the job better with more options. You can find the full syntax here. (Also read more on how this works internally in Oracle in this answer).

To answer the original question, here's the query:

SELECT * 
FROM   sometable
ORDER BY name
OFFSET 20 ROWS FETCH NEXT 10 ROWS ONLY;

(For earlier Oracle versions, please refer to other answers in this question)

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Examples:

Following examples were quoted from linked page, in the hope of preventing link rot.

Setup

CREATE TABLE rownum_order_test (
  val  NUMBER
);

INSERT ALL
  INTO rownum_order_test
SELECT level
FROM   dual
CONNECT BY level <= 10;

COMMIT;

What's in the table?

SELECT val
FROM   rownum_order_test
ORDER BY val;

       VAL
----------
         1
         1
         2
         2
         3
         3
         4
         4
         5
         5
         6
         6
         7
         7
         8
         8
         9
         9
        10
        10

20 rows selected.

Get first N rows

SELECT val
FROM   rownum_order_test
ORDER BY val DESC
FETCH FIRST 5 ROWS ONLY;

       VAL
----------
        10
        10
         9
         9
         8

5 rows selected.

Get first N rows, if N^th row has ties, get all the tied rows

SELECT val
FROM   rownum_order_test
ORDER BY val DESC
FETCH FIRST 5 ROWS WITH TIES;

       VAL
----------
        10
        10
         9
         9
         8
         8

6 rows selected.

Top x% of rows

SELECT val
FROM   rownum_order_test
ORDER BY val
FETCH FIRST 20 PERCENT ROWS ONLY;

       VAL
----------
         1
         1
         2
         2

4 rows selected.

Using an offset, very useful for pagination

SELECT val
FROM   rownum_order_test
ORDER BY val
OFFSET 4 ROWS FETCH NEXT 4 ROWS ONLY;

       VAL
----------
         3
         3
         4
         4

4 rows selected.

You can combine offset with percentages

SELECT val
FROM   rownum_order_test
ORDER BY val
OFFSET 4 ROWS FETCH NEXT 20 PERCENT ROWS ONLY;

       VAL
----------
         3
         3
         4
         4

4 rows selected.