Selecting N rows in SQL Server
As commented earlier, it's because you reached the number of rows of sys.columns
. Here is another way to generate list of numbers or what others call Numbers Table
or Tally Table
.
This uses cascaded CTE
s and is said to be the fastest way to create a Tally Table:
DECLARE @Range AS INT = 7374
;WITH E1(N) AS( -- 10 ^ 1 = 10 rows
SELECT 1 FROM(VALUES (1),(1),(1),(1),(1),(1),(1),(1),(1),(1))t(N)
),
E2(N) AS(SELECT 1 FROM E1 a CROSS JOIN E1 b), -- 10 ^ 2 = 100 rows
E4(N) AS(SELECT 1 FROM E2 a CROSS JOIN E2 b), -- 10 ^ 4 = 10,000 rows
E8(N) AS(SELECT 1 FROM E4 a CROSS JOIN E4 b), -- 10 ^ 8 = 10,000,000 rows
CteTally(N) AS(
SELECT TOP(@Range) ROW_NUMBER() OVER(ORDER BY(SELECT NULL))
FROM E8
)
SELECT * FROM CteTally
You could easily add another CTE if you need more than 10,000 rows.
For more information about Tally Table, read this excellent article by Jeff Moden.
For performance comparisons among ways to generate Tally Tables, read this.
Explanation taken from Jeff's article:
The CTE called
E1
(as in 10E1 for scientific notation) is nothing more than tenSELECT 1
's returned as a single result set.
E2
does aCROSS JOIN
ofE1
with itself. That returns a single result set of 10*10 or up to 100 rows. I say "up to" because if the TOP function is 100 or less, the CTE's are "smart" enough to know that it doesn't actually need to go any further andE4
andE8
won't even come into play. If theTOP
has a value of less than 100, not all 100 rows thatE2
is capable of making will be made. It'll always make just enough according to theTOP
function.You can follow from there.
E4
is aCROSS JOIN
ofE2
and will make up to 100*100 or 10,000 rows andE8
is aCROSS JOIN
ofE4
which will make more rows than most people will ever need. If you do need more, then just add anE16
as aCROSS JOIN
ofE8
and change the finalFROM
clause toFROM E16
.What's really amazing about this bad-boy is that is produces ZERO READS. Absolutely none, nada, nil.
One way to generate a large series of numbers would be to use a cross join
to create a cartesian product between two tables which will generate a set that is n^2
in size.
This approach however performs a lot worse than the solution put forward in the answer by Felix Pamittan and therefore shouldn't be used.
DECLARE @Range AS INT = 10000
;WITH CTE AS(
SELECT TOP (@Range) Duration = ROW_NUMBER() OVER(ORDER BY (SELECT NULL))
FROM sys.all_columns a CROSS JOIN sys.all_columns b
)
SELECT Duration from CTE
This would generate a set of 54375876 rows in your case. Instead of generating the rows on the fly you should consider creating a tally table suitable for your needs.