BS ISO/IEC 19075-5:2021 - Page 3

Information technology. Guidance for the use of database language SQL. Row pattern recognition | Status: Current

1 Scope 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.