Top "Aggregate" questions

Returning first row of group

I have a dataframe consisting of an ID, that is the same for each element in a group, two datetimes …

r aggregate plyr

Aggregate Function on Uniqueidentifier (GUID)

Let's say I have the following table: category | guid ---------+----------------------- A | 5BC2... A | 6A1C... B | 92A2... Basically, I …

sql sql-server guid aggregate uniqueidentifier

R- Collapse rows and sum the values in the column

I have the following dataframe (df1): ID someText PSM OtherValues ABC c 2 qwe CCC v 3 wer DDD b 56 ert EEE …

r unique aggregate rows collapse

How to aggregate some columns while keeping other columns in R?

I have a data frame like this: id no age 1 1 7 23 2 1 2 23 3 2 1 25 4 2 4 25 5 3 6 23 6 3 1 23 and I hope to aggregate the date frame by id …

r aggregate

Any reason for GROUP BY clause without aggregation function?

I'm (thoroughly) learning SQL at the moment and came across the GROUP BYclause. GROUP BY aggregates or groups the resultset …

sql mysql group-by aggregate

How do I concatenate strings in Entity Framework Query?

How do I concatenate strings in Entity Framework 4 I have a data from a column and I want to save …

sql entity-framework entity-framework-4 aggregate string-concatenation

Count totals by year and month

I have a table that looks like this: id,created,action 1,'2011-01-01 04:28:21','signup' 2,'2011-01-05 04:28:21',…

mysql date group-by aggregate

Aggregate vs Sum Performance in LINQ

Three different implementations of finding the sum of an IEnumerable < int> source are given below along with the …

c# performance linq sum aggregate

In aggregate: sum not meaningful for factors

I am trying something that should be simple, any hint on what is going on is very welcomed. I have …

r aggregate factors

Best way to convert Dictionary<string, string> into single aggregate String representation?

How would I convert a dictionary of key value pairs into a single string? Can you do this using LINQ …

c# linq .net-4.0 aggregate