Top 50 Data Engineer Interview Questions
The 50 most important questions to prepare for Data Engineer interviews. Questions from real interview reports rank first. Updated daily.
Merge two sorted arrays into one sorted array using a two-pointer linear scan.
Dropbox
TetraScience
BookingMerge two sorted singly linked lists into one sorted list by relinking existing nodes.
NeoDocto
Otter
SimplUse a hash map to find two array elements that sum to a target in O(n) time.
iCapital
Paycom
Blend360Find the first non-repeating character in a string using frequency counting and a second pass in O(n) time.
Cloudsek
Brightside Health
McAfeeUse GROUP BY and SUM to rank the top 10 customers by total revenue from a single sales table.
Housecall Pro
Equifax
XYZFind the second highest salary in each department without using aggregate functions.
Credit Genie
Devoteam
Cisco Restaurant + BarRewrite a slow PostgreSQL loan payment query to reduce scanned rows while preserving the required aggregated results.
AmeripriseEEltro Cyberchrome Private
EnergyHubFind the second highest distinct salary from a single table using basic PostgreSQL ordering and limiting.
eClinicalWorksNNeenOpal Canada
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