Friday, August 10, 2007

SQL Server random number generator

This SQL Script generates a random number between 1 and 5.

It demonstrates a few interesting ideas:
1) Temporary tables - These are in memory temporary tables (I use these all the time)
2) SQL Server looping with While (you may use these instead of cursors. I've heard cursors are slower)
3) Random number generation with newid() (select top 5 * from [table] order by newid() returns 5 random rows.

declare @tempTable table (column1 int) --declaring a temporary table
declare @i int
set @i =1
While @i <=1000000 begin insert into @temptable (column1) select abs(cast(cast(newid() as varbinary) as int))%5+1 set @i = @i +1 end

--select * from @temptable

select column1 as [value],count(*) as [Occurrences],
cast(count(*)*100 / cast((select count(*) from @temptable) as decimal) as int) as [Percentage] from @temptable
group by column1

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