Re: add more frame types in window functions (ROWS) - Mailing list pgsql-hackers

From Hitoshi Harada
Subject Re: add more frame types in window functions (ROWS)
Date
Msg-id e08cc0400911142343s20dd9b2dve37d41f24f1673f@mail.gmail.com
Whole thread Raw
In response to Re: add more frame types in window functions (ROWS)  (Andrew Gierth <andrew@tao11.riddles.org.uk>)
List pgsql-hackers
2009/11/15 Andrew Gierth <andrew@tao11.riddles.org.uk>:
> My thinking is that the executor definitely shouldn't be relying on it
> being a specific node type, but should just ExecEvalExpr it on the
> first call and store the result; then you don't have to know whether
> it's a Const or Param node or a more complex expression.

Yeah, so that we allow something like ROWS BETWEEN 1 + $1 PRECEDING
AND ... And to support RANGE BETWEEN n PRECEDING ..., we should make
datum to add or to subtract from current value on initial call anyway.

Regards,


-- 
Hitoshi Harada


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