Обсуждение: ROW or RANGE not optional in range specification
Either I'm confused about the syntax description rules or the documentation for this aspect of window definitions is wrong.
The expression:
[ RANGE | ROWS ] BETWEEN frame_start AND frame_end
means that the specification of range or rows is optional - but that doesn't appear to be the case...
The documentation should read:
{ RANGE | ROWS } BETWEEN frame_start AND frame_end
Same goes for the bare frame_start specification preceding the between version.
The bare version looks funny without tag but "ORDER BY idx BETWEEN 5 PRECEDING AND CURRENT ROW" isn't obviously wrong until you get a syntax error...
David J.
"David G. Johnston" <david.g.johnston@gmail.com> writes: > Either I'm confused about the syntax description rules or the documentation > for this aspect of window definitions is wrong. > The expression: > [ RANGE | ROWS ] BETWEEN frame_start AND frame_end > means that the specification of range or rows is optional - but that > doesn't appear to be the case... > The documentation should read: > { RANGE | ROWS } BETWEEN frame_start AND frame_end Yup, you're right. Thanks for spotting that! regards, tom lane