Given a table products with a B-tree index on product_id, what will the query optimizer most likely do when running:

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SQL - Indexes and Query Performance

Given a table products with a B-tree index on product_id, what will the query optimizer most likely do when running:
SELECT * FROM products WHERE product_id = 123;?

AUse the B-tree index to quickly locate the row with product_id 123

BPerform a full table scan ignoring the index

CUse a hash index lookup instead of the B-tree

DScan only the first 10 rows of the table

Step-by-Step Solution

Solution:

Step 1: Understand query condition and index
The query searches for a specific product_id value, which matches the indexed column.
Step 2: Predict optimizer behavior with B-tree index
The optimizer uses the B-tree index to quickly find the matching row without scanning the whole table.
Final Answer:
Use the B-tree index to quickly locate the row with product_id 123 -> Option A
Quick Check:
Indexed search = fast lookup [OK]

Quick Trick: Queries on indexed columns use B-tree for fast lookup [OK]

Common Mistakes:

Assuming full table scan always happens
Confusing B-tree with hash index usage
Thinking partial scan happens without index

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Given a table products with a B-tree index on product_id, what will the query optimizer most likely do when running:

Step 1: Understand query condition and index

Step 2: Predict optimizer behavior with B-tree index

Final Answer:

Quick Check:

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