Obfuscated Conditions

The following sections demonstrate some popular methods for obfuscating conditions. Obfuscated conditions are where clauses that are phrased in a way that prevents proper index usage. This section is a collection of anti-patterns every developer should know about and avoid.

Contents

1. Dates — Pay special attention to DATE types

2. Numeric Strings — Don’t mix types

3. Combining Columns — use redundant where clauses

4. Smart Logic — The smartest way to make SQL slow

5. Math — Databases don’t solve equations