Peter's answer is my favourite, too.
If you are looking for more details there is a quite good overview, IMO, here.
Especially interesting is to read the benchmarks.
Do it the hard way. Use the awesome MODEL
clause:
SELECT V
FROM DUAL
MODEL DIMENSION BY (0 R)
MEASURES (0 V)
RULES ITERATE (100) (
V[ITERATION_NUMBER] = ITERATION_NUMBER + 1
)
ORDER BY 1
SELECT * FROM `DUAL` WHERE id>0 AND id<101
The above query is written in SQL in the database.
Your question is difficult to understand, but if you want to select the numbers from 1
to 100
, then this should do the trick:
Select Rownum r
From dual
Connect By Rownum <= 100
Using Oracle's sub query factory clause: "WITH", you can select numbers from 1 to 100:
WITH t(n) AS (
SELECT 1 from dual
UNION ALL
SELECT n+1 FROM t WHERE n < 100
)
SELECT * FROM t;
Using GROUP BY CUBE
:
SELECT ROWNUM
FROM (SELECT 1 AS c FROM dual GROUP BY CUBE(1,1,1,1,1,1,1) ) sub
WHERE ROWNUM <=100;
You could use XMLTABLE
:
SELECT rownum
FROM XMLTABLE('1 to 100');
-- alternatively(useful for generating range i.e. 10-20)
SELECT (COLUMN_VALUE).GETNUMBERVAL() AS NUM
FROM XMLTABLE('1 to 100');
Another interesting solution in ORACLE PL/SQL:
SELECT LEVEL n
FROM DUAL
CONNECT BY LEVEL <= 100;
I created an Oracle function that returns a table of numbers
CREATE OR REPLACE FUNCTION [schema].FN_TABLE_NUMBERS(
NUMINI INTEGER,
NUMFIN INTEGER,
EXPONENCIAL INTEGER DEFAULT 0
) RETURN TBL_NUMBERS
IS
NUMEROS TBL_NUMBERS;
INDICE NUMBER;
BEGIN
NUMEROS := TBL_NUMBERS();
FOR I IN (
WITH TABLA AS (SELECT NUMINI, NUMFIN FROM DUAL)
SELECT NUMINI NUM FROM TABLA UNION ALL
SELECT
(SELECT NUMINI FROM TABLA) + (LEVEL*TO_NUMBER('1E'||TO_CHAR(EXPONENCIAL))) NUM
FROM DUAL
CONNECT BY
(LEVEL*TO_NUMBER('1E'||TO_CHAR(EXPONENCIAL))) <= (SELECT NUMFIN-NUMINI FROM TABLA)
) LOOP
NUMEROS.EXTEND;
INDICE := NUMEROS.COUNT;
NUMEROS(INDICE):= i.NUM;
END LOOP;
RETURN NUMEROS;
EXCEPTION
WHEN NO_DATA_FOUND THEN
RETURN NUMEROS;
WHEN OTHERS THEN
RETURN NUMEROS;
END;
/
Is necessary create a new data type:
CREATE OR REPLACE TYPE [schema]."TBL_NUMBERS" IS TABLE OF NUMBER;
/
Usage:
SELECT COLUMN_VALUE NUM FROM TABLE([schema].FN_TABLE_NUMBERS(1,10))--integers difference: 1;2;.......;10
And if you need decimals between numbers by exponencial notation:
SELECT COLUMN_VALUE NUM FROM TABLE([schema].FN_TABLE_NUMBERS(1,10,-1));--with 0.1 difference: 1;1.1;1.2;.......;10
SELECT COLUMN_VALUE NUM FROM TABLE([schema].FN_TABLE_NUMBERS(1,10,-2));--with 0.01 difference: 1;1.01;1.02;.......;10
A variant of Peter's example, that demonstrates a way this could be used to generate all numbers between 0 and 99.
with digits as (
select mod(rownum,10) as num
from dual
connect by rownum <= 10
)
select a.num*10+b.num as num
from digits a
,digits b
order by num
;
Something like this becomes useful when you are doing batch identifier assignment, and looking for the items that have not yet been assigned.
For example, if you are selling bingo tickets, you may want to assign batches of 100 floor staff (guess how i used to fund raise for sports). As they sell a batch, they are given the next batch in sequence. However, people purchasing the tickets can select to purchase any tickets from the batch. The question may be asked, "what tickets have been sold".
In this case, we only have a partial, random, list of tickets that were returned within the given batch, and require a complete list of all possibilities to determine which we don't have.
with range as (
select mod(rownum,100) as num
from dual
connect by rownum <= 100
),
AllPossible as (
select a.num*100+b.num as TicketNum
from batches a
,range b
order by num
)
select TicketNum as TicketsSold
from AllPossible
where AllPossible.Ticket not in (select TicketNum from TicketsReturned)
;
Excuse the use of key words, I changed some variable names from a real world example.
... To demonstrate why something like this would be useful
If you want your integers to be bound between two integers (i.e. start with something other than 1), you can use something like this:
with bnd as (select 4 lo, 9 hi from dual)
select (select lo from bnd) - 1 + level r
from dual
connect by level <= (select hi-lo from bnd);
It gives:
4
5
6
7
8
Source: Stackoverflow.com