SQL Index Fragmentation and Maintenance
SQL Server index fragmentation, reorganization, rebuilding, and concerns about using GUIDs as primary keys
Understanding and Mitigating Parameter Sniffing
Causes, impact, and solutions for parameter sniffing issues in SQL Server
Deadlocks in SQL Server
Overview of deadlocks, query patterns that cause them, and countermeasures
Clustered and Non-Clustered Indexes
How to check SQL Server clustered indexes, non-clustered indexes, index seek/scan, and execution plans