Logical operators allow your database queries to reflect the complex business rules of your application.
1The Strictness of AND
Use AND when you want to narrow down your results. Every AND you add acts like a new filter, making the result set smaller and more specific.
2The Inclusivity of OR
Use OR when you want to expand your results. It allows you to gather data from different segments into a single cohesive list.
3Negation with NOT
NOT is incredibly useful for finding exceptions. WHERE NOT status = 'shipped' helps you find all orders that still need attention, regardless of their specific stage.
