> [!Note] > `The Query Processor transforms T-SQL into an optimized execution plan and runs it efficiently through parsing, optimization, and execution phases.` 1. **Parsing & Binding** - Analyzes the T-SQL statement and builds a logical operator tree. - Validates syntax and resolves object names, data types, and schemas. 2. **Query Optimization** - Generates multiple possible execution plans from the logical tree. - Estimates cost for each plan using statistics (row counts, index selectivity). - Selects the lowest-cost plan for execution. 3. **Query Execution** - Executes the chosen plan operators in sequence (scans, joins, aggregates, etc.). - Manages parallelism, memory grants, and operator pipelines. - Caches the compiled plan in plan cache for reuse. --- ## References - Korotkevitch, D. (2022). _SQL Server advanced troubleshooting and performance tuning: Best practices and techniques_. O’Reilly Media. - Nevarez, B. (2022). _SQL Server query tuning and optimization: Optimize Microsoft SQL Server 2022 queries and applications_. Packt Publishing.