Which three are true about subqueries?（多选题）
A.A subquery can be used in a WHERE clause.
B.A subquery can be used in a HAVING clause.
C.=ANY can only evaluate the argument against a subcjuery if it returns two or more values.
D.<ANY returns true if the argument is less than the highest value returned by the subquery.
E.A subquery cannot be used in a FROM clause.
F.< any returns true if the argument is less than the lowest value returned by the subquery.
