本文档讨论了用于识别表的行中的模式的语法和语义，如ISO/IEC 9075-2中定义的，通常称为“SQL/RPR”。SQL/RPR定义了关于行模式识别的两个特征:-特征R010，“行模式识别:FROM子句”-特征R020，“行模式识别:窗口子句”这两个特征具有相当大的共同语法和语义，主要区别在于语法是放在FROM子句中还是放在窗口子句中。

This document discusses the syntax and semantics for recognizing patterns in rows of a table, as defined in ISO/IEC 9075-2, commonly called “SQL/RPR”.
SQL/RPR defines two features regarding row pattern recognition:
— Feature R010, “Row pattern recognition: FROM clause”
— Feature R020, “Row pattern recognition: WINDOW clause”
These two features have considerable syntax and semantics in common, the principle difference being whether the syntax is placed in the FROM clause or in the WINDOW clause.