SQL Server MVP Jeff Moden shows us a new very high performance method to convert an "Adjacency List" to “Nested Sets” on a million node hierarchy in less than a minute and 100,000 nodes in just seconds. Not surprisingly, the "steroids" come in a bottle labeled "Tally Table".
2014-09-19 (first published: 2012-11-13)
40,245 reads
It's a well known fact that Scalar UDFs are the stuff of performance nightmares in T-SQL. But are they really as bad as they say? SQL Server MVP Jeff Moden shows us that they might not really be as big a problem as you might think and what you can do when they actually are.
2014-06-24 (first published: 2012-08-01)
26,539 reads
A simple problem that can become complex in T-SQL. How do you find the rows that match 2 conditions, but not a third, in an efficient manner. MVP Jeff Moden gives us a solution.
2014-06-06 (first published: 2012-03-29)
41,349 reads
SQL Server MVP Jeff Moden walks us through the classic problem of finding all the "Active" rows for the previous month using start and end dates. This is excellent for those new to T-SQL.
2014-01-30
8,527 reads
Get correct answers to your SQL forum questions faster by making it easier to load your sample data and read your code.
2013-12-10 (first published: 2007-11-27)
212,719 reads
Another in the series of articles to help you "fill in the cracks" in your T-SQL knowledge. MVP Jeff Moden shows us a super simple, high performance method to solve this timeless problem.
2013-07-19 (first published: 2011-01-20)
25,487 reads
The Tally Table has proven to be a simple and elegant method for avoiding many varieties of RBAR. Unfortunately, one of its more common uses, that of a CSV splitter, has a well-known and serious performance problem. MVP Jeff Moden shows us what that problem is and how to correct it. (UPDATED with additional info and attachments on 5/12/2011).
2012-12-28 (first published: 2011-05-02)
136,676 reads
In this sequel to his first "Hierarchies on Steroids" article, SQL Server MVP Jeff Moden shows us how to build a pre-aggregated table that will answer most of the questions that you could ask of a typical hierarchy. Any bets on whether Santa is packin’ a Tally Table in his bag or not?
2012-11-15
19,199 reads
Another in our series of articles to help you fill in the cracks in your knowledge with SQL Spackle. MVP Jeff Moden shows us how IsNumeric works and how you should use it.
2012-09-14 (first published: 2010-12-01)
43,779 reads
Replacing multiple spaces with a single space is an old problem that people use loops, functions, and/or Tally tables for. Here's a set based method from MVP Jeff Moden.
2012-08-17 (first published: 2009-11-16)
63,140 reads
By Steve Jones
ochisia – n. the fear that the role you once occupied in someone’s life...
This is a quick blog post, mainly so I have the code available if...
Praise whatever deity you believe in, because it’s finally here, a tenant switcher for...
I've read lots of the horror stories about nested views in databases where they're...
Hello! How do I grant a user to read-write to a single database and...
When building statistics, there is the concept of density that refers to the duplicates in a table. How is this calculated?
See possible answers