Am Di., 10. Juli 2018 um 00:29 Uhr schrieb Tom Lane <tgl@sss.pgh.pa.us>:
I think what we really should be doing here is giving a parse error.
Yes, I agree. That's also what the SQL standard says.
ISO/IEC 9075-2:2016(E)
7.15 <window clause>
13 c) If GROUPS is specified, then:
i) Either WDEF shall contain a <window order clause>, or WDEF shall specify an <existing window name> that identifies a window structure descriptor that includes a window ordering clause.
What would you expect GROUPS mode to do without an ORDER BY to define the grouping?
I had no expectations, was just playing around with the new syntax.
