Optimizing the SQL Query Riddle: A Deep Dive into Data Modeling and T-SQL

Counting Distinct IDs for Each Day within the Last 7 Days using SQL

Finding Sailors Who Have Booked Every Boat: A Query-Based Approach

Optimizing SQL Queries for Conditional Summation

Understanding Group By Statements in SAS and SQL for Data Manipulation and Analysis Techniques

Creating a New Dummy Variable Based on Existing Dummy Variable Values in R using dplyr Package

Transforming Data from Long Format to Wide Format Using dcast() in data.table

Using Aggregate Function in R: Summarizing Data by Group