Una subconsulta (subquery) es una sentencia "select" anidada en otra sentencia "select", "insert", "update" o "delete" (o en otra subconsulta). Las subconsultas se emplean cuando una consulta es muy ...

Using SQL EXISTS The result of the EXISTS condition is a boolean value— True or False. SQL Server EXISTS can be used in SELECT, UPDATE, INSERT, or DELETE statements.

The EXISTS condition is an operator whose right operand is a subquery. The result of an EXISTS condition is true if the subquery resolves to at least one row. The result of a NOT EXISTS condition is ...