Top "Aggregate" questions

Multiple functions in a single tapply or aggregate statement

Is it possible to include two functions within a single tapply or aggregate statement? Below I use two tapply statements …

r aggregate tapply

NHibernate Criteria select items by the group by and sum of itemid within another table

public class SearchText { public virtual int Id { get; set; } public virtual string Text { get; set; } } public class SearchTextLog { public virtual …

nhibernate criteria aggregate nhibernate-projections

How to load extensions into SQLite?

I need a standard deviation function in SQLite. I have found one here: http://www.sqlite.org/contrib?orderby=date …

sql sqlite aggregate aggregate-functions standard-deviation

Performance of max() vs ORDER BY DESC + LIMIT 1

I was troubleshooting a few slow SQL queries today and don't quite understand the performance difference below: When trying to …

sql postgresql max aggregate sql-limit

Why can't indexed views have a MAX() aggregate?

I have been trying out a few index views and am impressed but I nearly always need a max or …

sql-server view indexing aggregate

Pandas groupby(),agg() - how to return results without the multi index?

I have a dataframe: pe_odds[ [ 'EVENT_ID', 'SELECTION_ID', 'ODDS' ] ] Out[67]: EVENT_ID SELECTION_ID ODDS 0 100429300 5297529 18.00 1 100429300 5297529 20.00 2 100429300 5297529 21.00 3 100429300 5297529 22.00 4 100429300 5297529 23.00 5 100429300 5297529 24.00 6 100429300 5297529 25.00 When I use …

python pandas group-by aggregate multi-index

Does COUNT(*) always return a result?

If I run a query such as: SELECT COUNT(*) as num FROM table WHERE x = 'y' Will it always return …

mysql sql aggregate

quick/elegant way to construct mean/variance summary table

I can achieve this task, but I feel like there must be a "best" (slickest, most compact, clearest-code, fastest?) way …

r aggregate plyr reshape2

Summarize data.table by group

I am working with a huge data table in R containing monthly measurements of temperature for multiple locations, taken by …

r data.table aggregate mean

Convert a "by" object to a data frame in R

I'm using the "by" function in R to chop up a data frame and apply a function to different parts, …

r dataframe aggregate