本文档讨论了在SQL中包含在线分析处理（OLAP）功能的语法和语义，如ISO/IEC 9075-2中所定义。它讨论了关于SQL语言的OLAP功能的以下特性:-特性T611，“基本OLAP操作”，-特性T612，“高级OLAP操作”，-特性T614，“NTILE函数”，-特性T615，“超前和滞后函数”，-特性T616，“超前和滞后函数的空处理选项”，-特性T617，“第一值和最后值函数”，-特性T618，“NTH_VALUE函数”，-特性T619，“嵌套窗口函数”，-特性T620，“窗口子句:组选项”，-特性T621，“增强型数值函数”

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”