Using n_distinct to Extract Unique Values by Specific Conditions in R Data Analysis

The Issue with dplyr's Group By and Summarise Functions for Handling Duplicate Values When Calculating Aggregates

Understanding Grouping and Aggregation in SQL: A Deep Dive into Using `GROUP BY` with Additional Columns

How to Use SUM Aggregation for Specific Columns Using GROUP BY Clause

Subsetting Table in R when IDs are Non-Unique and Values Match