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)
42,760 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)
27,707 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)
41,670 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
8,749 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)
218,637 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)
26,683 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)
141,156 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
20,113 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)
44,276 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)
64,956 reads
By Steve Jones
With the AI push being everywhere, Redgate is no exception. We’ve been getting requests,...
By Steve Jones
fawtle – n. a weird little flaw built into your partner that somehow only...
AWS recently added support for Post-Quantum Key Exchange for TLS in Application Load Balancer...
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Comments posted to this topic are about the item T-SQL in SQL Server 2025:...
On SQL Server 2025, I have a database that has this collation: SQL_Latin1_General_CP1_CI_AS. I decide I want to run this code:
SELECT UNISTR('*3041*308A*304C*3068 and good night', '*') AS 'A Classic';
I get this error:Msg 9844, Level 16, State 4, Line 24 The char/varchar input type uses an unsupported collation. Only a UTF8 collation is supported with char/varchar input type in UNISTR function.What is the easiest way to fix this error? See possible answers