Re: help with date_part & day of week

me(at)alternize(dot)com wrote:
> > You can really do it using CASE:
> >
> > CASE
> > WHEN dow() = 0 THEN 6
> > ELSE dow() - 1
> > END
>
> how good is this solution in regards to performance? i always thought CASE
> and the such should only be used for last resorts. and now there is also a
> date function involved that gets twice in 6/7 of all cases...
>
> regarding these concerns, can you give me your opinion on this solution i
> came up:
>
> SELECT ((date_part('dow', now()) + 6) % 7) AS weekday

I don't think CASE is any significant performance hit, certainly less
than a pl/pgsql function. Anyway, your solution looks even cleaner.

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