Indexing SQL Server Temporary Tables

データベースのインデックスの種類と内部の仕組み｜SQL Serverで数億規模のデータ量を扱ってみて

Index Scan vs Index Seek — The Real Reason Your SQL Queries Run Slow! When you try to fetch data like “Celestar from Employee table” without proper indexing, the SQL engine has no choice—it scans the entire table row by row. This is called an Index Scan, and it behaves just like a * full table scan*. Slow. Heavy. Time-consuming. But when your table has the right index (ex: EmployeeID, EmployeeName, Salary), the engine doesn’t waste time scanning everything. It jumps directly to the required reco