CASE statement in SQL

SQL Operators - How to Use Them to Query Your Databases

IF THEN logic with CASE - SQL Video Tutorial | LinkedIn Learning, formerly Lynda.com

SQL: IS NULL Condition

Understanding the SQL Server CASE statement

Is Null, If Null, and Is Not Null in SQL: Lesson 12 Free Beginner SQL Course

Using a SQL Server Case Statement for IF/Else Logic

SQL IF Statement for Conditional Logic

IF-THEN logic in SELECT and WHERE with CASE expressions in Oracle SQL