Posts about SQL techniques
Slowly changing dimension tables can be challenging to validate as the effective dates span records. The expectation is that for a given entity we have one or more records with a range of effective...
You have a query, maybe one you didn’t write. How do you test and validate that the joins are correct? Let’s walk through a simple example. I’m running MySQL with the employees sample database...
This page describes a high level approach for naming database objects. It is a combination of the abbreviations that I have used used at many clients. It also includes some basic principles from...
Introduction You know your way around the select statement, you can join tables in various ways, use aggregate functions, can alter existing tables and create new objects, etc. But sometimes your SQL...