【国外标准】 Information technology - Guidance for the use of database language SQL - Part 5: Row pattern recognition

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.