Simple SQL: Random Thoughts

How does one get a truly random sample of data of a certain size from a SQL Server database table. Well, there are simple non-portable tricks one can use, such as the NewID() function, but then refining those can be tricky. Take the Rand() function for a start. Can it really provide you with a truly random number? Why doesn't the TABLESAMPLE clause give you a set number of rows? Joe Celko scratches his head a bit, explains some of the issues and invites some suggestions and tricks from readers.

Fun Conversions

The Basics of Good T-SQL Coding Style – Part 4: Performance

There are several obvious problems with poor SQL Coding habits. It can make code difficult to maintain, or can confuse your team colleagues. It can make refactoring a chore or make testing difficult. The most serious problem is poor performance. You can write SQL that looks beautiful but performs sluggishly, or interferes with other threads. A busy database developer adopts good habits so as to avoid staring at execution plans. Rob Sheldon gives some examples.

Logical Query Processing Filters

Compressing Integers

When sp_HelpText is not so helpful!

A note of caution on the use of sp_helptext to script out objects.

More Order of Processing

Saving Master Keys

Calculating the Tally

Creating a large database