Weimao Ke wrote:
Hi,
I need a special aggregation function. For instance, given the
following table data:
aid | cat | weight
----------+---------+---------
a1 | Drama | 1
a1 | Romance | 6
a1 | Short | 1
a1 | Other | 7
a2 | Comedy | 1
a2 | Drama | 2
a3 | Drama | 1
a3 | Adult | 2
a3 | Comedy | 1
a3 | Other | 1
I want to group by "aid" and choose the category (i.e., "cat") with
the largest "weight":
aid | max_weighted_cat
----+---------------------
a1 | Other
a2 | Drama
a3 | Adult
Any ideas? Thank you! :)
Should be able to do this with a standard max() aggregate.
select aid, cat, max(weight)
from table
group by aid, cat;
Jeff
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