databases.md

The Next 50 Years of Databases - 2015

Things I Wished More Developers Knew About Databases

Modern Data Lakes Overview

Terrifically Simple JSON

SQL

An Easy Introduction to SQL for Data Scientists

Three must know SQL questions to pass your data science interview

[Modern Data Practice and the SQL Tradition](Modern Data Practice and the SQL Tradition)

Mastery with SQL - a hands-on practical course for anyone who wants to learn modern SQL

https://www.linkedin.com/posts/eric-weber-060397b7_data-statistics-datascience-activity-6667857833138229248-mg_6

Basic:

1. SELECT and WHERE for filtering and selection.
2. COUNT, SUM, MAX for aggregating data.
3. DISTINCT, GROUP BY, COUNT DISTINCT for producing useful distinct lists and distinct aggregates.
4. LEFT and INNER JOIN when/where to use them.

The use of UNION seemed to fall in basic for some, intermediate for others.

Intermediate:

1. Handling NULLs creatively (e.g. with COALESCE)
2. Subqueries and the impact of subqueries on efficiency of the query. Some basic ability to tune the query.
3. Using LEFT AND INNER JOIN as a means of filtering without using the WHERE statements.
4. Self joins for leveraging a table against itself.

Advanced:

1. Use of indexes in querying to make operations faster.
2. Window functions like RANK and DENSE RANK.
3. Stored procedures.
4. UDFs (user defined functions)
5. Triggers
6. PIVOT and UNPIVOT