Which two statements are true regarding subqueries? (Choose two.)
A.
Only two subqueries can be placed at one level.
B.
A subquery can be used to access data from one or more tables or views.
C.
If the subquery returns 0 rows, then the value returned by the subquery expression is
NULL. D. The columns in a subquery must always be qualified with the name or alias of
the table used. E. A subquery in the WHERE clause of a SELECT statement can be
nested up to three levels only.
ANS : B & C
B, C