← 🗄️ Data & SQL Engineering

Core

Indexing Strategies in SQL: B-Tree, Composite, and Covering

Pick an index by access pattern: B-tree for ranges, hash for equality, covering for index-only scans, plus composite column order and selectivity.

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COURSES COVERING THIS TOPIC

No lesson covers this one directly yet. These teach the surrounding topic from the beginning.

Applied AI Engineering·The interviewPremium12mTurning this course into a study planA concrete four-week plan mapping the seven modules onto the question bank, plus what to do differently if your interview is next week rather than next month.

RELATED CONCEPTS

Query Execution and Optimization Partitioning and Clustering SQL Joins Deduplication (Exact and Fuzzy)

PRACTICE THIS IN REAL QUESTIONS

SQL & Data EngineeringSCD Type 2 in Delta Lake: track history with one atomic MERGE.→SQL & Data EngineeringGroup a stream of user events into sessions in SQL (30-minute inactivity gap) using window functions.→SQL & Data EngineeringTop-N per group in SQL: ROW_NUMBER vs RANK vs DENSE_RANK.→SQL & Data EngineeringA SQL query is slow. How do you diagnose and optimize it?→SQL & Data EngineeringYou have a wide table with one column per month. How do you unpivot it into tidy (key, month, value) rows?→SQL & Data EngineeringGiven rows with start and end timestamps, merge all overlapping intervals per user in SQL.→

COMPANIES THAT ASSUME THIS

Scale AI Palantir Databricks Snowflake Zendesk Clay

NEXT IN DATA & SQL ENGINEERINGPartitioning and Clustering→