aggregate operators sqlsupports all of the

Question

Aggregate Operators SQL

Supports all of the aggregate operators mentioned in the theory book and many more besides. The syntax, however, involves an unusual trick that SQL calls a scalar subquery. A scalar subquery is a table expression that satisfies all of the following conditions:

1. It is enclosed in parentheses.
2. It appears where a scalar expression is expected.
3. The result of the enclosed table expression has exactly one column and at most one row.