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Generating Non-uniform Random Numbers with SQL


Generating Non-uniform Random Numbers with SQL

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dwain.c
dwain.c
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Comments posted to this topic are about the item Generating Non-uniform Random Numbers with SQL


My mantra: No loops! No CURSORs! No RBAR! Hoo-uh!

My thought question: Have you ever been told that your query runs too fast?

My advice:
INDEXing a poor-performing query is like putting sugar on cat food. Yeah, it probably tastes better but are you sure you want to eat it?
The path of least resistance can be a slippery slope. Take care that fixing your fixes of fixes doesn't snowball and end up costing you more than fixing the root cause would have in the first place.


Need to UNPIVOT? Why not CROSS APPLY VALUES instead?
Since random numbers are too important to be left to chance, let's generate some!
Learn to understand recursive CTEs by example.
Splitting strings based on patterns can be fast!
My temporal SQL musings: Calendar Tables, an Easter SQL, Time Slots and Self-maintaining, Contiguous Effective Dates in Temporal Tables
GPO
GPO
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A stunning contribution to the discussion Dwain. The SQL Server world just got a little better.

:-)

One of the symptoms of an approaching nervous breakdown is the belief that one's work is terribly important.
Bertrand Russell

dwain.c
dwain.c
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GPO (7/2/2012)
A stunning contribution to the discussion Dwain. The SQL Server world just got a little better.


Thanks GPO, for the kudos and the inspiration! The article was fun to research and to write.


My mantra: No loops! No CURSORs! No RBAR! Hoo-uh!

My thought question: Have you ever been told that your query runs too fast?

My advice:
INDEXing a poor-performing query is like putting sugar on cat food. Yeah, it probably tastes better but are you sure you want to eat it?
The path of least resistance can be a slippery slope. Take care that fixing your fixes of fixes doesn't snowball and end up costing you more than fixing the root cause would have in the first place.


Need to UNPIVOT? Why not CROSS APPLY VALUES instead?
Since random numbers are too important to be left to chance, let's generate some!
Learn to understand recursive CTEs by example.
Splitting strings based on patterns can be fast!
My temporal SQL musings: Calendar Tables, an Easter SQL, Time Slots and Self-maintaining, Contiguous Effective Dates in Temporal Tables
Jonathan AC Roberts
Jonathan AC Roberts
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Nice article but a few charts of what the distributions look like would have been nice.
Lowell
Lowell
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Excellent contribution Dwain; I added this to my toolbox!

Lowell
--help us help you! If you post a question, make sure you include a CREATE TABLE... statement and INSERT INTO... statement into that table to give the volunteers here representative data. with your description of the problem, we can provide a tested, verifiable solution to your question! asking the question the right way gets you a tested answer the fastest way possible!
Etopap
Etopap
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Dwain, awesome article! Fun to read. Thanks a lot for sharing it.
Sue Amin
Sue Amin
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Thank you for showing how to represent Mathematics with SQL. Reminded me of Fortran! Awesome article... I need to study and understand certain areas of this article. Good research topic. Sue
G-Dub
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Extremely useful! Thank you, thank you, thank you!
Bryant McClellan
Bryant McClellan
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Excellent post, both for the concise definitions and the code explanations.

For the Poisson distributions consider the use of a CLR. That my eliminate the side-effects issue.

------------
Buy the ticket, take the ride. -- Hunter S. Thompson
Sean Lange
Sean Lange
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This is excellent Dwain!!! Definite addition to the toolbox.

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Need to split a string? Try Jeff Modens splitter.

Cross Tabs and Pivots, Part 1 – Converting Rows to Columns
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Understanding and Using APPLY (Part 1)
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