Inevitably, every DBA is eventually asked to delete, merge, or otherwise report on duplicate data. There are many tools at our disposal to make this task both simple and efficient to complete. Read on for simple steps and examples to effectively deal with duplicate data.  Read more...

Views that use implicit conversion to return result sets may use a different query plan than the statement executed in query analyzer.  Read more...

There are times where you need to write a single T-SQL statement that is able to return different T-SQL expressions based on the evaluation of another expression. When you need this kind of functionality you can use the CASE expression or IIF function to meet this requirement. In this Stairway level Gregory Larsen reviews the CASE and IIF syntax and showing you examples of how the CASE expression and IIF function.  Read more...

Sometimes we need to break down a complex problem into a multiple stage solution to achieve optimal performance  Read more...

There are times when retrieving data for complex business requirement requires you to temporarily store one or more results sets for a short period of time. Typically these temporary tables are stored in the scope of the current connection, but they may also need to be available across multiple connections.   Read more...

How to use the EXCEPT statement to perform row differences.  Read more...

The handling of dates in TSQL is complex - when SQL Server was Sybase, it was forced by the lack of prevailing standards in SQL to create its own ways of processing and formatting dates and times. Joe Celko looks forward to a future when it is possible to write standard SQL date-processing code with SQL Server.  Read more...

This level discusses how to use a database VIEW to simplify your Transact-SQL(T-SQL) code. By understanding how to use a VIEW you will be able to better support writing T-SQL code to meet complex business requirements. In this article I will be discussing what a database VIEW is and then providing a number of examples to help you understand how you can use a VIEW to implement different coding scenarios.  Read more...

When you've got only a single effective date on a record and you need to artificially create the effective end date based on a following row in T-SQL, the techniques discussed in this article will help you decide what is best.  Read more...

PARSENAME is perhaps the most infrequently used built-in documented function in SQL Server. SQL Server Microsoft Certified Master Wayne Sheffield shows why this nifty function ought to be included in your SQL toolbox.  Read more...

Allowing your application to generate your SQL can be a really bad decision.  Read more...

This stairway level will expand on the subquery topic by discussing a type of subquery known as a correlated subquery, and explores what a correlated subquery is and how it is different from a normal subquery.  Read more...

The way in which SQL Server chooses to join your tables in a query can dramatically affect performance. In this article, Jason Brimhall explains how a hash match works and shows some performance numbers.  Read more...

The client wants to change a date based business rule  Read more...

Steve Jones has a problem with the inconsistency of the CREATE TABLE statement in SQL Server and has an idea on what to do.  Read more...

sp_ExecuteSQL can be used to dynamically execute T-SQL code. Learn how to use it and how to add parameters to control what code is executed.  Read more...

Show the results for a date even if there is no data.  Read more...

Learn how to avoid complex date calculations and increase performance using calendar tables in this article from Todd Fifield.  Read more...

What are your options for sending a variable number of choices in a parameter to a stored procedure? Alex Grinberg looks at three techniques you can use.  Read more...

Window Functions in SQL greatly simplify a whole range of financial and statistical aggregations on sets of data. Because there is less SQL on the page, it is easy to assume that the performance is better too: but is it? Dwain gets out the test harness to investigate.  Read more...