Databases

I think this is important to include, you need to get the data from somewhere after all.

SQL Server - Quick Introduction to SQL Server and why you might use it.

Basic SQL - Basic intro to SQL

DBBrowser - A database development tool for use with SQL Lite files

Stored Procedure - Stored procedures or packages in SQL Server or Oracle etc. to automate tasks.

Extracting Words from a column - Extract words from a column in SQL Server

Basic SQL Joins - How to connect tables in SQL, the thing I find a pain in Office.

The CASE Statement - Great tool in SQL

Analytical Function - Very powerful SQL functions