Re: BETWEEN [SYMMETRIC | ASYMMETRIC]

>
> I don't really see this as important enough to justify introducing a
> nonstandard syntax for it...
>
>             regards, tom lane

Sorry to quote like this, it makes me feel like a real nerd. :)

This quote from the SQL standard (1999) has it:

       8.3  <between predicate>        Function        Specify a range comparison.        Format        <between
predicate>::=             <row value expression> [ NOT ] BETWEEN               [ ASYMMETRIC | SYMMETRIC ]
<rowvalue expression> AND <row value expression>        Syntax Rules        1) If neither SYMMETRIC nor ASYMMETRIC is
specified,then           ASYMMETRIC is implicit.        2) Let X, Y, and Z be the first, second, and third <row value
       expression>s, respectively.        3) "X NOT BETWEEN SYMMETRIC Y AND Z" is equivalent to "NOT ( X
BETWEENSYMMETRIC Y AND Z )".        4) "X BETWEEN SYMMETRIC Y AND Z" is equivalent to "((X BETWEEN           ASYMMETRIC
YAND Z) OR (X BETWEEN ASYMMETRIC Z AND Y))".        5) "X NOT BETWEEN ASYMMETRIC Y AND Z" is equivalent to "NOT ( X
     BETWEEN ASYMMETRIC Y AND Z )".        6) "X BETWEEN ASYMMETRIC Y AND Z" is equivalent to "X>=Y AND X<=Z".
AccessRules           None.        General Rules           None.        Conformance Rules        1) Without Feature
T461,"Symmetric <between predicate>",           conforming SQL language shall not specify SYMMETRIC or
ASYMMETRIC.       2) Without Feature S024, "Enhanced structured types", no subfield           of the declared type of a
<rowvalue expression> that is simply           contained in a <between predicate> shall be of a structured
type.                                 
 

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