Learn how to use common table expressions to simplify your code. Replace temp tables and correlated subqueries with this cool T-SQL feature.  Read more...

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 for replacing multiple spaces from MVP Jeff Moden.  Read more...

Revisiting his very popular article on the running total and ordinal rank problems, MVP Jeff Moden brings us a detailed analysis of how you might want to implement a solution in T-SQL.  Read more...

Indexing is important for improving performance, but do you know that a lack of indexes might actually cause things to stop working? Alok Dwivedi brings us a very interesting scenario where the lack of an index causes a problem with concurrency.  Read more...

That said, even though my personal focus is pretty much OO, I still miss stuff. SQL Server 2005 came out with the CROSS APPLY and OUTER APPLY operators and I have just started learning how to use APPLY in the last month or so. When I think I have it figured out, I am fortunate enough that some of you are interested in reading about my understanding of the technology.  Read more...

Is there a way to not allow users to use SELECT * in their queries? New author AJ Raghuram has an interesting solution that can prevent this in code.  Read more...

A step by step example of how to add pre-calculated closing balances through T-SQL and semi-additive measures from Johan Åhlén.  Read more...

Query performance can be affected by many different factors. This article introduces another best practice of how and how not to use a function within your T-SQL statements.  Read more...

How can you delete only some duplicates? Without Identity's, Temp tables, Cursors, loops or ROW_NUMBER()? Would you believe, go back to the 70's?  Read more...

An interesting use of T-SQL to run a stored procedure as part of a SELECT statement to get a result set to be used and combined with other tables. From Eli Leiba, learn how you can build a stored procedure into your queries.  Read more...

No, I’m not talking about a Dickens novel. I’m talking about the number of characters in a string. I had a painful time recently because of the word “characters.”   Read more...

This objective of the article is to give readers in depth understanding of INNER JOIN with different joining conditions.   Read more...

Joe Celko explores the dangers of muddling correlation and causation, emphasises the importance of determining how likely it is that a correlation has occurred by chance, and gets stuck into calculating correlation coefficients in SQL. Along the way, Joe illustrates the consequences of leaping to the wrong conclusion from correlations with tales of Pop Dread.   Read more...

Often in database design we store different values in rows to take advantage of a normalized design. However many times we need to combine multiple rows of data into one row for a report of some sort. New author Carl P. Anderson brings us some interesting T-SQL code to accomplish this.  Read more...

An "old" subject is revisted where "newbies" can learn the methods and veteran users can get more performance out of the code.  Read more...

New author Cliff Corder has a SQL Server function to report on a 4-4-5 Calendar Accounting Year.  Read more...

Jacob Sebastian takes a look at some different ways to write your WHERE clauses. A good basic article for those starting to work with T-SQL.  Read more...

SQL WHERE clause optimization is important to get maximum performance from a query. If an index exists on a column you obviously want the query to use it...   Read more...

JSON is Javascript Object Notation and it's a format for exchanging data. New author Ric Vander Ark brings us an article that shows how to implement a function to split out the data into a table format and gives a number of examples for different data.  Read more...

Building a tally table is a common T-SQL problem that many new developers struggle with. Lynn Pettis brings us an article that shows how to use CTEs to accomplish this.  Read more...

The ROW_NUMBER function has drastically changed the way we can write a number of queries in T-SQL. New author Francis Rodrigues brings us a few places where this function can improve the efficiency of your code.  Read more...

Use sysindexes\DMVs insead of select count(*) to retreive table row counts  Read more...

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 for replacing multiple spaces from MVP Jeff Moden.  Read more...