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.