Subquery Types
Subqueries can be specified in many places:
With aliases. For more information, see Subqueries with Aliases.
With IN or NOT IN. For more information, see Subqueries with IN and Subqueries with NOT IN.
In UPDATE, DELETE, and INSERT statements. For more information, see Subqueries in UPDATE, DELETE, and INSERT Statements.
With comparison operators. For more information, see Subqueries with Comparison Operators.
With ANY, SOME, or ALL. For more information, see Comparison Operators Modified by ANY, SOME, or ALL.
With EXISTS or NOT EXISTS. For more information, see Subqueries with EXISTS and Subqueries with NOT EXISTS.
In place of an expression. For more information, see Subqueries Used in Place of an Expression.