Use the CASE expressions for conditional expressions in Derby.

You can place a CASE expression anywhere an expression is allowed. It chooses an expression to evaluate based on a boolean test.

CASE WHENbooleanExpressionTHENthenExpression[ WHENbooleanExpressionTHENthenExpression]... ELSEelseExpressionEND

*ThenExpression* and *elseExpression* are
both expressions that must be type-compatible. For built-in types, this means
that the types must be the same or a built-in broadening conversion must exist
between the types.

-- returns 3 VALUES CASE WHEN 1=1 THEN 3 ELSE 4 END

-- returns 7 VALUES CASE WHEN 1 = 2 THEN 3 WHEN 4 = 5 THEN 6 ELSE 7 END