"Joel Jacobson" <joel@xxxxxxxxxxxx> writes: > Is it idiomatic and safe to use > SELECT > CASE boolean_expression WHEN TRUE THEN function_with_side_effects() END > in a query to ensure the function_with_side_effects() is only > execute if boolean_expression is true? As long as function_with_side_effects() is properly marked volatile, it's safe (whether it's idiomatic is in the eye of the beholder). The issue with the divide-by-zero example is that the division operator is marked immutable, so if the planner sees that it has constant arguments it will try to simplify-on-sight, even within a CASE expression. regards, tom lane
