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.
How the Main System Views Connect
Learn how the main system views connect through object_id, schema_id, index_id, and column_id so catalog joins stay accurate.
SQL SERVER – Explanation SQL SERVER Merge Join
What a Merge Join needs and when it is fast: two sorted inputs with matching column types. Presorted B-tree indexes make it quick, extra sorts make it costly.
SQL SERVER – Good, Better and Best Programming Techniques
My notes for a programmers meeting on Good, Better and Best Programming Techniques in SQL Server, plus a funny bug ticket about a client who got no email.
SQL SERVER – Query to Retrieve the Nth Maximum Value
Finding the nth Maximum Value means deciding how ties should count. Here, I rank distinct known salaries.
SQL Server Interview Questions and Answers Part 6
Interview Questions and Answers Part 6 covers the six properties of relational tables and de-normalization, adding redundant data to help performance.