Let’s talk about the MERGE statement

Specifically, why we should avoid using the MERGE statement. I was going to make a quick blog post on why we should avoid using the MERGE statement in hopes of convincing my fellow co-workers to avoid them (regardless of what database vendor we are using). Really I was just going to provide a bunch of … Continue reading Let’s talk about the MERGE statement →

Automating Full Outer Joins

Recently I helped out on a project where a company was moving to a new CRM system. Part of the validation process was to compare identical old vs new tables, column by column, and report any discrepancies between each value.... and there were dozens of tables and hundreds of columns. So I decided to automate … Continue reading Automating Full Outer Joins →

Permutations, Combinations, Sequences and Random Numbers

Hello everyone! I am back with a new set of puzzles (18 to be exact). As the title suggests, these 18 puzzles revolve around permutations, combinations, sequences, and random numbers. And of course the solutions are provided as well (written in Microsoft SQL Server's T-SQL). This set of puzzles includes using recursion to create a … Continue reading Permutations, Combinations, Sequences and Random Numbers →

Behavior of NULLS

One of the more interesting aspects of database management systems is the concept of NULL markers. Because they are a source of great confusion and much debate (for more on this debate, I highly recommend C.J. Dates' Database in Depth: Relational Theory for Practitioners) I decided to create a summary of all the different SQL … Continue reading Behavior of NULLS →