Re: Something like 'to_days' in postgresql? Help with a

On Thu, 2003-12-11 at 08:44, Alan T. Miller wrote:
> I am migrating an application over from mysql to postgresql and am a little
> confused on how to write the following query in PostgreSQL. The date
> functions and syntax is a world apart from MySQL and what I am used to. To
> sum it up, I want to select a count of all records in a table that have been
> added in the last 90 days. My current table has a field called 'created'
> which is a timestamp. In MySQL the query goes as follows...
>
> SELECT COUNT(*) AS total
> FROM orders
> WHERE id = 'id'
> AND TO_DAYS(NOW()) - TO_DAYS(created) <= 90

CURRENT_DATE - created <= 90

> If someone thinks this is easy enough, it would be even more helpful if
> someone could suggest the most efficient was to do the same query but
> perhaps return the total for the last 7 days, the last 30 days, and the last
> 90 days in the same query. I know I can run the query three times but I was
> hoping for a suggestion that might be more efficient.

I don't think you do it in SQL without three separate queries.  You
can't use GROUP BY because the conditions are not mutually exclusive.

Use a procedural language.

--
Oliver Elphick                                Oliver.Elphick@lfix.co.uk
Isle of Wight, UK                             http://www.lfix.co.uk/oliver
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