How does join order and indexing affect performance in multi-table joins?

Problem Statement

Explanation

Optimizers try different join orders to minimize intermediate row counts. Starting with the most selective filters reduces data early and speeds the whole plan. Good statistics and appropriate indexes help the optimizer choose correctly. Indexes on join keys enable efficient lookups and hash or merge joins. Composite indexes that match the join and filter columns in order can be especially powerful in star schemas.

Code Solution

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SELECT f.sale_id, d.date_id
FROM fact_sales f
JOIN dim_date d ON d.date_id = f.date_id
WHERE d.yyyy_mm = 202509;

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How does join order and indexing affect performance in multi-table joins?

Problem Statement

Explanation

Code Solution

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How does join order and indexing affect performance in multi-table joins?

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