Florian Schricker <fschric...@gmail.com>
wrote:
> Schema of DB (simplified):
> - Oper (string)
> - Product (string)
> - Category (string)
> - Name (string)
> - CreateTS (Timestamp)
> - Value (Double)
>
> Primary keys are Oper, Product, Category, Name and CreateTS
>
> What I could not figure out: Suppose I want to select rows by "op",
> "cat", "product" and get all measurements "m1" to "m4" with the latest
> timestamp in CreateTS.
>
> So for a set of measurements identified by everything but their name
> select the latest rows as defined by the timestamp.
select * from mytable t1
where oper=:oper and product=:product and category=:category and
createTs = (select max(createTs) from mytable t2
where t1.oper = t2.oper and t1.product = t2.product and t1.category =
t2.category and t1.name = t2.name
);
Igor Tandetnik
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