[Solved] If a table sales has an index on sale_date, what is the expected result of this query?SELECT COUNT(*) FROM sales WHERE sale_date BETWEEN '2023-01-01' AND '2023-01-31'; | PostgreSQL

PostgreSQL - Indexing Strategies

If a table sales has an index on sale_date, what is the expected result of this query?

SELECT COUNT(*) FROM sales WHERE sale_date BETWEEN '2023-01-01' AND '2023-01-31';

AThe index will speed up counting rows in the date range

BThe index will slow down the query

CThe query will ignore the index and scan all rows

DThe query will return zero rows

Step-by-Step Solution

Solution:

Step 1: Understand index range scans
Indexes on date columns allow efficient range queries like BETWEEN to quickly find matching rows.
Step 2: Analyze the query
The query counts rows in a date range, so the index on sale_date will speed up the search.
Final Answer:
The index will speed up counting rows in the date range -> Option A
Quick Check:
Range queries on indexed columns use index range scans [OK]

Quick Trick: Indexes speed up range queries on indexed columns [OK]

Common Mistakes:

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If a table sales has an index on sale_date, what is the expected result of this query?