Re: Variable constants ?

On 2019-08-16 14:50, Rich Shepard wrote:
> On Fri, 16 Aug 2019, Charles Clavadetscher wrote:
> 
>> Another way to keep a history is using a daterange instead of two 
>> columns for start and end date. Something like
>> 
>> create table labor_rate_mult (
>>  rate         real primary_key,
>>  validity    daterange not null
>> )
> 
> Charles,
> 
> Just out of curiosity, what is the range for a rate that is still 
> current?
> Does it change every day?
> 
> Regards,
> 
> Rich

Hi Rich

That would be a range with an empty upper bound. Let's say that the rate 
is valid since 2019-08-14 then the range would look like

[2019-08-14,)

A query to find the current rate would look like:

SELECT rate
FROM labor_rate_mult
WHERE validity @> CURRENT_DATE;

Here you can find documentation on the range types (cool stuff I 
believe):

https://www.postgresql.org/docs/11/rangetypes.html

Regards
Charles

-- 
Charles Clavadetscher
Swiss PostgreSQL Users Group
Treasurer
Neugasse 84
CH – 8005 Zürich

http://www.swisspug.org

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