Composite keys need a complete pair match when the allowed values are defined together. I don’t split the components into independent lists. Doing so can admit combinations that were never allowed.
SQL SERVER – 2005 Explanation Left Semi Join Showplan Operator and Other Operator
What the Left Semi Join showplan operator means, along with Left Anti Semi Join, Right Anti Semi Join and other joins you see in a text execution plan.
A Quote of the Day From a Table, With No Repeats Until All Are Used
Build a quote of the day table that rotates without repeats, handles concurrent requests, and supports a stable date-based selection.
SQL SERVER – 2005 Comparison EXCEPT operator vs. NOT IN
The EXCEPT operator returns distinct rows from the left query with no match on the right, just like NOT IN. Both give the same plan, but EXCEPT reads simpler.
What Is NULL in SQL Server? The Value That Isn’t a Value
NULL in SQL Server is not zero and not an empty string. It means the value is unknown, and that changes every comparison you write. Why equals never matches, the NOT IN trap that returns nothing, and where NULL is allowed to live.
Testing an Application for SQL Injection
Testing an application for SQL injection on a safe copy reveals response clues and unsafe query construction before repair.
Collecting Server Facts Into One Table Every Night
Collect Server Facts each night to track SQL Server versions, settings, databases, and file sizes in a practical history table.