Itzik Ben-Gan

Itzik
Ben-Gan

Itzik Ben-Gan is a contributing editor to SQL Server Pro and a cofounder of SolidQ. He teaches, lectures, and consults internationally. He's a SQL Server MVP and is the author of several books about T-SQL, including Microsoft SQL Server 2012 High-Performance T-SQL Using Window Functions (Microsoft Press).

Check out Itzik's Puzzled by T-SQL blog.
Twitter: @ItzikBenGan

Articles
sequence
Identifying a Subsequence in a Sequence, Part 3 2
Itzik Ben-Gan presents two reader-submitted solutions for identifying a subsequence within a sequence, both of which far surpass his original solutions.
SQL spelled out on keyboard
Optimization Tips for Multiple Range Predicates, Part 2 1
Itzik covers three practical examples affected by the multiple range predicate problem, as well as optimization tips to improve performance.
SQL database code
Optimization Tips for Multiple Range Predicates, Part 1
Multiple range predicates can be the source of query performance problems. Itzik presents some tips for optimizing your solutions.
prescription drugs
T-SQL Interval Graphs Challenge, Part 2 1
In Part 2 of this article, Itzik Ben-Gan uses T-SQL to provide the complete solution to an interval packing problem related to drug prescriptions modeled as interval graphs.
interval graph
T-SQL Interval Graphs Challenge, Part 1
Itzik Ben-Gan uses T-SQL to find an efficient solution to an interval packing problem related to drug prescriptions modeled as interval graphs.
Identifying a Subsequence in a Sequence, Part 2 4
Itzik Ben-Gan explores three set-based T-SQL solutions to find the best approach for identifying a subsequence within a sequence.
DNA strands representing iterative solution to finding subsequence in sequence
Identifying a Subsequence in a Sequence, Part 1 7
Itzik Ben-Gan explores several iterative T-SQL solutions to find the best approach for identifying a subsequence within a sequence.
Infinite loop to represent the SQL Server Halloween problem
Divide and Conquer Halloween
Query plans of T-SQL solutions based on the Decrease and Conquer algorithm contain extra work to deal with Halloween protection. Itzik presents an alternative generic pattern that removes the need for Halloween protection.
abstract clock
Intervals and Counts, Part 4
Learn how to compute the count of active intervals at the beginning of every fixed interval.
men on track running intervals with stopwatch
Intervals and Counts, Part 3
Many types of tasks involve handling date and time intervals and computing related counts. Learn how to compute the maximum count of concurrent sessions during every fixed interval within a certain input period.
IT/Dev Connection conference logo
T-SQL Querying and Query Tuning Full-Day Seminar at IT/Dev Connections in Vegas, Sept. 30
Join me for a full-day workshop about T-SQL querying and query tuning improvements in the last major releases of SQL Server (2012, 2008 and 2005).
time interval
Intervals and Counts, Part 2
Itzik presents an improved solution to last month's task using the APPLY operator for computing counts during discrete intervals, as well as a solution for computing counts during discrete intervals including packing logic.
intervals and counts
Intervals and Counts, Part 1
Learn how to identify discrete intervals and counts of overlapping source intervals.
Interval Queries in SQL Server 2
Interval-related queries tend to perform very inefficiently in SQL Server. Itzik presents an ingenious solution based on the Relational Interval Tree (RI-tree) model.
Unwanted T-SQL Expression Failures 1
Itzik discusses expression failures in T-SQL queries and presents a proposal to Microsoft for a new T-SQL feature called TRY_EXPRESSION that would provide a more general solution for preventing expression failures.

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Browse back issues of SQL Server Pro, from January 2007 through the last issue published in April 2014. Find the back issues here.

 

From the Blogs
Jul 28, 2015
blog

AlwaysOn Availability Groups and SQL Server Jobs, Part 29: Practical Implementation Tips

My initial goal in writing this series of posts was to outline some of the concerns surrounding Availability Groups (AGs) and SQL Server Agent Jobs – and call out how there is virtually no guidance from Microsoft on this front and then detail some of the pitfalls and options available for tackling this problem domain. I initially expected this series of posts to have between 25 and 30 posts – according to some of the early outlines I created ‘way back when’....More
Jul 6, 2015
blog

AlwaysOn Availability Groups and SQL Server Jobs, Part 28: Additional Options for Tackling Jobs Failover

Throughout this series of posts I’ve taken a somewhat pessimistic view of how SQL Server Agent jobs are managed within most organizations – meaning that most of the code and examples I’ve provided up until this point were based on assumptions about how CHANGE to jobs is managed. That pessimism, to date, has come in two forms:...More
Jul 1, 2015
blog

AlwaysOn Availability Groups and SQL Server Jobs, Part 27: Options and Concerns for More Advanced Deployments

In this series of posts I’ve called out some of the concerns related to SQL Server AlwaysOn Availability Groups and their interaction with SQL Server Agent jobs – both in the form of Batch Jobs (see post #3) and backups....More
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