Re: Implement for window functions - Mailing list pgsql-hackers

On 1/1/21 10:21 PM, Zhihong Yu wrote:
> Krasiyan:
> Happy New Year.
> 
> For WinGetFuncArgInPartition():
> 
> +           if (target > 0)
> +               step = 1;
> +           else if (target < 0)
> +               step = -1;
> +           else
> +               step = 0;
> 
> When would the last else statement execute ? Since the above code is
> for WINDOW_SEEK_CURRENT, I wonder why step should be 0.

Hi.

"lag(expr, 0) over w" is useless but valid.
-- 
Vik Fearing