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Interview Questions

Real questions from top companies in SQL Β· hard

700+ Easy450+ Medium650+ Hard
All CategoriesBehavioralSpark/Big DataSQLPython/CodingSystem Design/ArchitectureCloud/ToolsGeneral/Othereasymediumhard
1

What is a Common Table Expression (CTE), and when would you use it?

SQLhardbigqueryoptimizationsnowflake2 min read
AccentureCognizantEPAMYash Technologies
β†’
2

What is the difference between a primary key and a unique key?

SQLhardsparksql2 min read
AccentureCognizantEPAMYash Technologies
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3

Explain Fact and Dimension Tables with examples.

SQLhardjoin0.6 min read
DatameticaDeloitteIncedo
β†’
4

Joins and window functions - INNER, LEFT, RIGHT, FULL OUTER, ROW_NUMBER(), RANK(), DENSE_RANK()

SQLhardjoinpartitionwindow0.7 min read
FordKPMGNihilent
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5

Difference Between Internal and External Tables in BigQuery

SQLhardbigqueryoptimizationpartition0.6 min read
EYIncedoTech Mahindra
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6

How do you optimize a long-running SQL query?

SQLhardjoinoptimizationpartition0.6 min read
AareteDunnhumbyIncedo
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7

Cloud Architecture - explain

SQLhardjoinoptimizationpartition3.6 min read
Nagarro
β†’
8

Consolidate hotel reviews and create a dashboard. Design a data model for the reviews.

SQLhardjoinoptimizationpartition3.6 min read
Expedia
β†’
9

Create Spark Session, read CSV, join, and write as table. Provide example code.

SQLhardetljoinoptimization0.3 min read
FedEx Dataworks
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10

Data Warehouse Design from scratch

SQLhardjoinoptimizationpartition3.6 min read
Walmart
β†’
11

Describe a challenging project where you optimized a complex ETL process.

SQLhardetljoinoptimization0.5 min read
Goldman Sachs
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12

Describe a situation where you had to redesign a data model to meet changing business needs

SQLhardjoinoptimizationpartition3.6 min read
Kagina
β†’
13

Design a Custom API that can query a backend server and return customer data such as the number of orders placed by a user based on their user ID

SQLhardjoinoptimizationpartition3.6 min read
Meesho
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14

Design a daily ETL pipeline to ingest API data into BigQuery.

SQLhardbigqueryetljoin3.6 min read
Google
β†’
15

Design a financial database system focusing on database models, schema design, partition keys, and query optimization techniques.

SQLhardjoinoptimizationpartition3.6 min read
Flipkart
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16

Design a relational data model for a sales database, incorporating normalization techniques

SQLhardjoinoptimizationpartition3.6 min read
Morgan Stanley
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17

Design a structure (data model) that allows efficient querying of movies based on multiple search criteria (title, genre, actor, director).

SQLhardjoinoptimizationpartition3.6 min read
Wayfair
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18

Design the data model for an ETL pipeline that ingests data from a database and loads it into Snowflake

SQLhardetljoinoptimization3.6 min read
Meesho
β†’
19

Designing backend architecture for SQL Warehouse?

SQLhardjoinoptimizationpartition3.6 min read
Snowflake
β†’
20

Designing scalable data models - explain approach

SQLhardjoinoptimizationpartition3.6 min read
Lumiq
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