Back to Categories

Data Engineer Interview Questions

55 questions to help you prepare for your next interview.

ACID Transactions on Data Lakes

Array Aggregation

Backfilling Historical Data

Change Data Capture (CDC)

Row vs Columnar Storage

Creating an External Table

Creating a View

Creating a Staging Table

Data Lake vs Data Warehouse

Data Quality (Null Checks)

Data Integrity Checks

Date Dimension Generation

Dealing with Timezones

Deduplicating Data with ROW_NUMBER()

Deduplicating logs (ROW_NUMBER)

Distributed Joins & Shuffling

Transform Data (ELT style)

Transform Data (ELT style)

Flattening JSON

Handling JSON Data

Handling Outliers (Z-score concept)

Hashing for CDC

Idempotency in Data Pipelines

Incremental Loads & High Watermarks

Incremental Loads (Delta)

Handling Late-Arriving Facts

Loading CSV Data (COPY)

Medallion Architecture Layers

OLAP Aggregation (ROLLUP)

OLAP vs OLTP Databases

OLAP Aggregation

Parquet vs CSV Storage

Partition Pruning

Querying a Partition

Querying a Partition

SCD Type 2 Filter

Handling Schema Drift

SCD Type 1 (Overwrite)

SCD Type 2 (Historical Tracking)

SCD Type 2 Filter

Snowflake Schema Design

Designing a Star Schema

Star Schema Query

Star Schema Query

Stream Processing Windowing

String Manipulation (Regex)

Generating Surrogate Keys

Natural vs Surrogate Keys

Type Casting (CAST)

Unnesting Arrays

The MERGE Statement

UPSERT / MERGE Statement

Running Total with Window Frames