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DwainCSQL

Dwain Camps is a seasoned project manager specializing in business solutions delivered through software development and implementation. Because performance often takes the forefront when it comes to customer satisfaction in software applications, his technical focus is in high-performance T-SQL.

Stupid T-SQL Tricks – Part 1: Logarithms

Not just for math geeks, logarithms and their inverse functions (the exponentials) can have useful and often unexpected capabilities in T-SQL.

    “Heeeeeere’s Johnny!” – Ed McMahon introducing Johnny Carson for the Tonight Show

If you’re old enough to remember the Tonight Show hosted by Johnny Carson, how can you not… Read more

0 comments, 1,089 reads

Posted in DwainCSQL on 1 May 2014

Using the T-SQL MERGE Statement

In SQL Server 2008, Microsoft added a new SQL query type: the MERGE statement. This flexible query provides the ability to perform INSERTs, UPDATEs and even DELETEs all within a single statement. Used in combination with Common Table Expressions (CTEs), this can be a powerful tool to replace multiple… Read more

0 comments, 844 reads

Posted in DwainCSQL on 13 April 2014

The One Million Row T-SQL Test Harness

So far in our blogs, we have talked a bit about performance, but today we’re going to show you a way you can confirm without doubt that you’re writing high-performance T-SQL code. This extremely valuable technique is something Developers and Testers alike should be familiar with.

Why one million (1M)… Read more

1 comments, 2,566 reads

Posted in DwainCSQL on 8 April 2014

Manipulating Dates and Times in T-SQL

In SQL 2008, Microsoft introduced some new date and time data types to augment the options available in prior versions. The full list of these data types with detailed explanations can be found in Microsoft Books on Line (BOL), but we’ll list them here with a very brief description.

Read more

0 comments, 3,303 reads

Posted in DwainCSQL on 4 April 2014

Make it Work, Make it Fast, Make it Pretty

When I first heard this, it struck me as being a remarkably concise wisdom applicable to virtually any programming task. The entire quotation is actually:

“Make it work, make it fast, then make it pretty… and it isn’t finished until it is pretty!”

SQL MVP Jeff Moden (RedGate’s 2011… Read more

1 comments, 264 reads

Posted in DwainCSQL on 1 April 2014

Calendar Tables in T-SQL

In an earlier blog, we covered a type of auxiliary table (the Tally Table) that can provide a lot of querying flexibility if you have one in your database or construct one in-line to your query. Today we’re going to talk about another: the Calendar table.

The basic concept… Read more

1 comments, 2,259 reads

Posted in DwainCSQL on 30 March 2014

Tally Tables in T-SQL

The Tally (or Numbers) table is one of the most useful constructs in intermediate-level SQL. Have you ever written a T-SQL WHILE loop? How about a CURSOR? If your answer to either of those questions is yes, you’ve probably been coding some really poor-performing SQL and you may not even… Read more

2 comments, 461 reads

Posted in DwainCSQL on 27 March 2014

Getting an INDEX SEEK to Speed up LIKE “%string%” Searches

In today’s blog I will attempt to challenge the popularly held notion that LIKE “%string%” wildcard searches must be slow (Sargability: Why %string% Is Slow).

A Sample Table Populated with 10 Million Rows of Test Data

In order to do this, we’ll need a large table of test… Read more

2 comments, 248 reads

Posted in DwainCSQL on 26 March 2014

Common Table Expressions in SQL

In SQL Server 2005, Microsoft introduced the Common Table Expression (CTE).  CTEs share similarities with VIEWS and derived tables, but are really not the same as either.  Oracle SQL also supports CTEs and while the syntax is basically the same, some of the properties that we’ll discuss may be slightly… Read more

3 comments, 294 reads

Posted in DwainCSQL on 23 March 2014

The T-SQL ROW_NUMBER() Function

If you learn one new T-SQL (i.e., Microsoft SQL Server) concept today it should be ROW_NUMBER().  Introduced in SQL 2005, this function is one of 4 window ranking functions (the others are RANK(), DENSE_RANK() and NTILE()).  Oracle SQL has a similar capability.

Let’s first create some sample data we can… Read more

1 comments, 249 reads

Posted in DwainCSQL on 22 March 2014