信息技术数据库语言.数据库语言SQL的使用指南.第9部分:联机分析处理（OLAP）能力

This document discusses the syntax and semantics for including online analytic processing (OLAP) capabilities in SQL, as defined in ISO/IEC 9075-2. It discusses the following features regarding OLAP capabilities of the SQL language: — Feature T611, "Elementary OLAP operations", — Feature T612, "Advanced OLAP operations", — Feature T614, "NTILE function", — Feature T615, "LEAD and LAG functions", — Feature T616, "Null treatment option for LEAD and LAG functions", — Feature T617, "FIRST_VALUE and LAST_VALUE functions", — Feature T618, "NTH_VALUE function", — Feature T619, "Nested window functions", — Feature T620, "WINDOW clause: GROUPS option", — Feature T621, "Enhanced numeric functions".