Ali Piroozi wrote > Hi > Which equivalence rule from those are listed in > email's attachment are implemented in postgresql? > where are them?
What do you mean by "where"? The various JOINS and UNION/INTERSECT/DIFFERENCE are all defined capabilities. SQL is not purely relational in nature so some of the mathematical rules may not be exactly implemented as theory would dictate but largely they are present. I would suggesting providing more context as to why you are asking this as people are more likely to provide help at this level of technical depth if they know why; and can frame their answers more appropriately. David J. -- View this message in context: http://postgresql.1045698.n5.nabble.com/Equivalence-Rules-tp5794035p5794069.html Sent from the PostgreSQL - hackers mailing list archive at Nabble.com. -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers