Evaluating How Filtering Options Affect T-SQL Performance
The many popular rules concerning T-SQL filtering operators can't be trusted implicitly; instead, you should evaluate your options explicitly.
by John Magnabosco
January 3, 2008
iltering is an important aspect of writing most complex queries. While there may be instances where you don't need a filter, such as a simple query that retrieves a list of all U.S. states, in the majority of cases you need to filter the data to a more precise set. For example, you might need to obtain a list of all U.S. states that begin with the letter "I."
Developers and DBAs have many operators available to perform such filters. Query performance is definitely a very high consideration when deciding which operator to use. There are some experts who claim that certain operators generally perform better than others, and provide rules of thumb to guide your choices. While these claims may be generally true, there are a number of influences on query performance in any individual case that can prove more important than the general rule. Basing the decision to select an operator strictly on a rule of thumb over the study of individual query usage and execution plans could result in a query that has less than optimal performance.
It's quick, easy and you get access to all the articles on DevX.
This registration/login is to allow you to read articles on devx.com. Already a member?
To become a member of DevX.com create your Member Profile by completing the form below. Membership is free!
iltering is an important aspect of writing most complex queries. While there may be instances where you don't need a filter, such as a simple query that retrieves a list of all U.S. states, in the majority of cases you need to filter the data to a more precise set. For example, you might need to obtain a list of all U.S. states that begin with the letter "I."
