Which approach often improves performance when an outer table is large and a correlated subquery is slow?

Problem Statement

Explanation

Correlated subqueries can execute once per outer row. A join lets the optimizer find an efficient join order and use indexes on the join keys. Ensure the join does not multiply rows unintentionally. Use grouping or semi-join style predicates if you only need existence.

Code Solution

SolutionRead Only

SELECT o.*
FROM orders o
JOIN customers c ON c.id = o.customer_id
WHERE c.vip = true;

Practice Sets

This question appears in the following practice sets:

CTEs, Subqueries & Advanced Joins

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Which approach often improves performance when an outer table is large and a correlated subquery is slow?

Problem Statement

Explanation

Code Solution

Practice Sets

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Master Interviews Anywhere, Anytime

Which approach often improves performance when an outer table is large and a correlated subquery is slow?

Problem Statement

Explanation

Code Solution

Practice Sets

Related Questions

Which SQL statement retrieves all columns and rows from a table named employees?

Which clause filters rows before aggregation and affects which rows are grouped?

What is the default sort order when ORDER BY is used without ASC or DESC?

Which construct is commonly used to paginate results in SQL engines like Postgres and MySQL?

Which predicate correctly checks for missing values in standard SQL?

More from SQL & Databases

Master Interviews
Anywhere, Anytime