This statement is ANSI SQL:2011 compliant.
Vantage does not enforce the ANSI restriction that value_expression_1 must be a deterministic function. In particular, Vantage allows the function RANDOM to be used in value_expression_1.
Note that if RANDOM is used, nondeterministic behavior may occur, depending on whether value_expression_1 is recalculated for each comparison to value_expression_n.