Categories / group-by
Transforming Data from Long Format to Wide Format Using dcast() in data.table
Using Aggregate Function in R: Summarizing Data by Group
Understanding Grouping and Aggregation in SQL: A Deep Dive into Using `GROUP BY` with Additional Columns
Implementing Time Lag in R with dplyr and data.table
Calculating Percentage of Terminated Employees by Department in R: A Comparative Analysis of dplyr, data.table, and Base R
How to Select Latest Submission for Each Subject Using SQL GROUP BY as Inner Query