SQL 2005 Dev
The SQLCAT team blog has a great tip on deleting rows efficiently to help preventing blocking and minimize log file growth http://sqlcat.com/msdnmirror/archive/2009/05/20/fast-ordered-delete.aspx.
Louis Davidson (Dr. SQL) has a great book on the subject, but he also posted a great shorter version on simple-talk. Always a good reminder for us all...http://www.simple-talk.com/sql/database-administration/ten-common-database-design-mistakes/
Lookup tables or Entiry-Attribute-Value (EAV) tables are often used in SQL programming. Joe as always gives some great advice on how to properly design these kind of tables. http://www.simple-talk.com/sql/t-sql-programming/avoiding-the-eav-of-destruction/ His use of a view to prevent SQL engine from intent locking is a great idea that is new to me, I will have to remember that one.
The guys over at less than dot have a great top 10 SQL Server functions you should know, that you probably have ignored until now (if you read it). http://wiki.lessthandot.com/index.php/Ten_SQL_Server_Functions_That_You_Have_Ignored_Until_Now
If you are using the Visual Studio Team System Database Edition (Data Dude), you will want to upgrade to the latest version that came out at end of April 2009. http://www.microsoft.com/downloads/details.aspx?FamilyID=bb3ad767-5f69-4db9-b1c9-8f55759846ed&displaylang=en
Reason's to update:
I want to create a compendium of cheat sheet sites that I think are good for SQL Server. And if I can't find anything good, I was going to create my own.
SQL Server DBA focused
A simplified BOL site includes more than DBA info - http://www.ss64.com/sql
Pinal Dave has attempted to create a one page version for SQL 2008.
If you need to select a column of data (vertical selection as apposed to row based selection) in the results window of Management Studio (SSMS) you can by holding down the Alt key first before you select the data. You can copy, cut, paste in the window to get the order you want. This works in code windows also.
You have to set the Options in SSMS to get this to work properly. Under Tools|Options|Query Results|SQL Server|Results to Text, select drop down option for Output Format to be Column Aligned and check box next to Include column headers in the result set.
SQLServerCentral author Jeff Moden has a great introductory write up on the uses of Nums/Numbers/Tally tables for ultimate performance out of SQL queries. There are more uses than just replacing cursors and while loops, but his use of cross joins was new to me and very cool.