A colleague pointed me to a nice cheat sheet for SQL Server developers. It contains:

- A checklist for writing fast queries
- Sargability of queries
- A checklist for creating indexes
- A legend of the 'Execution Plan Icons', including some optimizing tips and tricks.
- All datatypes, including memory-usage and indication for best performing types
- All string functions
- All system functions
- All date and time functions
- A list of all dateparts
- The cursor functions
- The mathematical functions

Source: http://www.dotnet4all.com/snippets/2008/04/factsheet-for-sql-server-developers.html

Direct link: http://www.dotnet4all.com/snippets/factsheet%20SQL%20Server.pdf