Top "Group-by" questions

Does T-SQL have an aggregate function to concatenate strings?

Possible Duplicates: Implode type function in SQL Server 2000? Concatenate row values T-SQL I have a view which I'm querying that …

sql-server sql-server-2005 tsql group-by aggregate-functions

dplyr issues when using group_by(multiple variables)

I want to start using dplyr in place of ddply but I can't get a handle on how it works (…

r group-by dplyr compound-key

group by dates in mongodb

I am working on a project in which I am tracking number of clicks on a topic. I am using …

date group-by mongodb

python pandas, DF.groupby().agg(), column reference in agg()

On a concrete problem, say I have a DataFrame DF word tag count 0 a S 30 1 the S 20 2 a T 60 3 an …

python pandas group-by split-apply-combine

SQL Query to get column values that correspond with MAX value of another column?

Ok, this is my query: SELECT video_category, video_url, video_date, video_title, short_description, MAX(video_id) FROM …

mysql sql group-by max aggregate-functions

GROUP BY - do not group NULL

I'm trying to figure out a way to return results by using the group by function. GROUP BY is working …

mysql sql group-by

Update Statement using Join and Group By

I have written the below Update Statement, but it shows the error such as "Incorrect syntax near the keyword 'GROUP'." …

sql sql-server-2008 join group-by update-statement

SQL Server Update Group by

I'm trying to execute this on MS-SQL but returns me an error just at the Group by line update #temp …

sql group-by sql-update

pyspark collect_set or collect_list with groupby

How can I use collect_set or collect_list on a dataframe after groupby. for example: df.groupby('key').collect_…

list group-by set pyspark collect

LINQ Group By Multiple fields -Syntax help

What is the correction needed for example 2 inorder to group by multiple columns Example 1 var query = from cm in cust …

c# linq group-by