This document describes two types of conditional expressions in SQL called CASE statements: CASE (Switch) and CASE (If). CASE (Switch) evaluates an expression and assigns a value based on strict equality matches to WHEN clauses, defaulting to an ELSE value. CASE (If) evaluates conditions in WHEN clauses using comparison operators, assigning values accordingly and defaulting to an ELSE value if no matches. Both provide syntax examples to demonstrate their usage.