Data exploration and descriptive or comparative statistics are very important tasks that have to be done repeatedly and iteratively during every data science project. This gives us better insight into the data that we want to process throughout all projects. T-SQL aggregate queries are an important part of data exploration.
A T-SQL aggregate query is a kind of query that basically summarizes groups of records from underlying datasets and typically provides aggregated numeric values for each group of records generated from the dataset. Groups of records are not needed for every case or every assignment. Such aggregation queries give an aggregation of summarized values over whole underlying datasets.
The simplest aggregation query does not require grouping. With or without grouping, aggregate queries use special kinds of functions, called aggregate functions...