SQL Window Functions: Summing Values Across Categories Within a Variable

Using Aggregate Functions and Joining Tables to Find Matching Department Hires

Understanding MySQL's Grouping Conundrum: Adding a Column Count to a Table Without Grouping

Creating a Loop that Iteratively Aggregates Data for Sequentially Larger Cluster Sizes in R

Conditional Aggregation for Multiple Columns from One Column in MS Access: A Practical Guide

Postgres JSON Aggregation for Multi-Level Table Analysis

Recreate Missing Data in R: Using dplyr and Complete() Function

Filtering SQL Result by Condition to Receive Only One Row per Customer for Each Product Type.

Joining Tables by Pieces: How to Count Groups in MySQL

How to Achieve Conditional Model Results with PostgreSQL's bool_or Function and Advanced Techniques