What is SQL Server query execution pipeline from query parsing to result delivery?

SQL Server executes queries through parsing, binding, optimization, execution, and result streaming stages.

A query goes through multiple internal phases. First, the parser validates syntax and builds a parse tree. Next, the algebrizer resolves object names, data types, and expands views into a logical query tree. Then the optimizer generates multiple candidate execution plans using cost-based analysis. After selecting the cheapest plan, the execution engine runs operators like scans, joins, and sorts using iterator model. Finally, results are streamed back to the client in batches. Each stage interacts with metadata, statistics, and memory/CPU resources.