Which is often faster when deduplicating before a join inflates rows?

Problem Statement

Explanation

De-duplicating early on the side that causes multiplicity prevents row explosion and shrinks the join inputs. That reduces memory, sorts, and downstream aggregation cost. This pattern is especially useful when joining many-to-many relationships or dimension tables with duplicated keys.

Code Solution

SolutionRead Only

WITH d AS (
  SELECT DISTINCT customer_id FROM clicks WHERE dt=:d
)
SELECT ... FROM d JOIN customers c ON c.id=d.customer_id;

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Query Plans & Performance Tuning

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Which is often faster when deduplicating before a join inflates rows?

Problem Statement

Explanation

Code Solution

Practice Sets

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Master Interviews Anywhere, Anytime

Which is often faster when deduplicating before a join inflates rows?

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