3. Key Lookups and Cardinality Estimation (41 min)

Why does one query get wildly different execution plans? Learn how statistics influence your query plans, discover how to see your own statistics, and understand how stats help build memory grants.

We finished part 3 with two similar-looking queries that produce very different behavior: one does a seek, and the other does a scan. Now you’ll learn why, plus add yet another index to make this query go faster, and then discuss the drawbacks of too many indexes.