What is the best way to create and populate a numbers table?

Question

I\'ve seen many different ways to create and populate a numbers table. However, what is the best way to create and populate one? With \"best\" being defined from most to l

Answer 1

I know this thread is old and answered, but there is a way to squeeze a little extra performance out of Method 7:

Instead of this (essentially method 7 but with some ease of use polish):

DECLARE @BIT AS BIT = 0
IF OBJECT_ID('tempdb..#TALLY') IS NOT NULL
  DROP TABLE #TALLY
DECLARE @RunDate datetime
SET @RunDate=GETDATE()
SELECT TOP 10000 IDENTITY(int,1,1) AS Number
    INTO #TALLY
    FROM sys.objects s1       --use sys.columns if you don't get enough rows returned to generate all the numbers you need
    CROSS JOIN sys.objects s2 --use sys.co
ALTER TABLE #TALLY ADD PRIMARY KEY(Number)
PRINT CONVERT(varchar(20),datediff(ms,@RunDate,GETDATE()))+' milliseconds'

Try this:

DECLARE @BIT AS BIT = 0
IF OBJECT_ID('tempdb..#TALLY') IS NOT NULL
  DROP TABLE #TALLY
DECLARE @RunDate datetime
SET @RunDate=GETDATE()
SELECT TOP 10000 IDENTITY(int,1,1) AS Number
    INTO #TALLY
    FROM        (SELECT @BIT [X] UNION ALL SELECT @BIT) [T2]
    CROSS JOIN  (SELECT @BIT [X] UNION ALL SELECT @BIT) [T4]
    CROSS JOIN  (SELECT @BIT [X] UNION ALL SELECT @BIT) [T8]
    CROSS JOIN  (SELECT @BIT [X] UNION ALL SELECT @BIT) [T16]
    CROSS JOIN  (SELECT @BIT [X] UNION ALL SELECT @BIT) [T32]
    CROSS JOIN  (SELECT @BIT [X] UNION ALL SELECT @BIT) [T64]
    CROSS JOIN  (SELECT @BIT [X] UNION ALL SELECT @BIT) [T128]
    CROSS JOIN  (SELECT @BIT [X] UNION ALL SELECT @BIT) [T256]
    CROSS JOIN  (SELECT @BIT [X] UNION ALL SELECT @BIT) [T512]
    CROSS JOIN  (SELECT @BIT [X] UNION ALL SELECT @BIT) [T1024]
    CROSS JOIN  (SELECT @BIT [X] UNION ALL SELECT @BIT) [T2048]
    CROSS JOIN  (SELECT @BIT [X] UNION ALL SELECT @BIT) [T4096]
    CROSS JOIN  (SELECT @BIT [X] UNION ALL SELECT @BIT) [T8192]
    CROSS JOIN  (SELECT @BIT [X] UNION ALL SELECT @BIT) [T16384]
ALTER TABLE #TALLY ADD PRIMARY KEY(Number)
PRINT CONVERT(varchar(20),datediff(ms,@RunDate,GETDATE()))+' milliseconds'

On my server this takes ~10 ms as opposed to the ~16-20 ms when selecting from sys.objects. It also has the added benefit of not being dependent on how many objects are in sys.objects. While it's pretty safe, it's technically a dependency and the other one goes faster anyway. I think the speed boost is down to using BITs if you change:

DECLARE @BIT AS BIT = 0

to:

DECLARE @BIT AS BIGINT = 0

It adds ~8-10 ms to the total time on my server. That said, when you scale up to 1,000,000 records BIT vs BIGINT doesn't appreciably affect my query anymore, but it still runs around ~680ms vs ~730ms from sys.objects.