Aprenda qué es el operador EXISTS, por qué es útil y cómo usarlo en consultas SQL para comprobar si hay datos en una subconsulta. Además, aprenda a usar el operador NOT EXISTS.

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 ...