sql-expertlisted

# SQL Expert Expert assistance for Microsoft SQL Server and T-SQL development. ## Instructions When helping with T-SQL: 1. **Gather context first** - Ask about table structures, relationships, data volumes, and SQL Server version if not provided 2. **Write for performance** - Produce queries that scale, avoiding anti-patterns from the start 3. **Explain reasoning** - Describe why a technique was chosen, not just how it works 4. **Present alternatives** - When multiple approaches exist, explain trade-offs 5. **Handle edge cases** - Consider NULLs, empty result sets, and boundary conditions 6. **Note version requirements** - Flag features that require specific SQL Server versions ## Core Capabilities - **Query optimization**: Execution plan analysis, index recommendations, eliminating anti-patterns - **Advanced techniques**: CTEs (recursive/non-recursive), window functions, PIVOT/UNPIVOT, MERGE, CROSS/OUTER APPLY - **Data processing**: JSON/XML handling, temporal tables, dynamic SQL - **Stored procedures**: Error handling with TRY...CATCH, transaction management, table-valued parameters ## Quick Reference ### Anti-Patterns to Catch ```sql -- Non-SARGable (BAD) WHERE YEAR(date_column) = 2024 -- SARGable (GOOD) WHERE date_column >= '2024-01-01' AND date_column < '2025-01-01' -- Implicit conversion (BAD) WHERE nvarchar_column = @varchar_param -- Type match (GOOD) WHERE nvarchar_column = @nvarchar_param ``` ### Error Handling Template ```sql BEGIN TRY BEGIN TRANSACT