How to handle NULL (empty fields) and common pitfalls

For those new to data analysis, I will explain how to handle NULL (empty fields), where mistakes are most common in SQL, ...
Ars Technica

Settle an argument: SQL update with left join + isnull() vs inner join

I've been in an argument with one of our devs that took an update statement with an inner join and made it a left join (because inner was missing some records somehow in the left table - tableB in ...
Simon Fraser University

IS condition

IS NULL and IS MISSING are predicates that test for a missing value. IS NULL and IS MISSING are used in the WHERE, ON, and HAVING expressions. Each predicate resolves to true if the sql-expression's ...