Sparse Column feature was introduced in SQL Server 2008. They are just ordinary columns that have an optimized storage for null values. We can consider sparse columns to reduce (20 percent to 40 ...

Warns on suboptimal CREATE TABLE statements during development Enforces strict alignment in CI/CD pipelines Audits existing tables and generates optimized migration scripts The problem is that ...

COUNT(*) counts all rows in the result set, regardless of whether any columns contain NULL values. It uses an optimized internal mechanism that doesn’t require reading specific column data. Instead, ...

SQL SELECT カラム名1, 集合関数(カラム名2) FROM テーブル名 GROUP BY カラム名1 カラム名1でグルーピングしたカラム名1と集合関数(カラム名2)を取得する。