14일차 # 6-10: Nested Subquery vs. Correlated Subquery

  * Nested Subquery: 내부 쿼리를 먼저

    - The inner query executes first and finds a value

    - The outer query executes once, using the value from the inner query

  * Correlated Subquery: 외부 쿼리를 먼저

    - Get a candidate row (fetched by the outer query)

    - Execute the inner query using the value of the candidate row

    - Use the values resulting from the inner query to qualify or disqualify the candidate

    - Repeat until no candidate row remains