Test specifications
Available Language(s):



15 questions

Suggested timelimit:

45 minutes


Subqueries, EXISTS, IN Operators

Grouping, Aggregate Functions, HAVING Clause

Joins, Queries

Miscellaneous: Ranking Functions, Foregin Key, Union Operator, NULLs

The Kandio Method

Kandio’s assessment tests let you assess the candidates, employees, agencies or freelancers you have concerning any PostgreSQL task you might have.

Remember that Kandio offers guidelines on which programmers to proceed with, and which ones to discard. Kandio will give you reliable directions about things programmers should know about, but a programmer can be excellent, even if he does not know about all of these things.

We suggest that you use our tests before your interview process to know which ones actually to talk to. The final Kandio report should be a piece of conversation with the strong candidates, rather than a disqualifying process in a late stage interview process.

The test and how it’s structured

PostgreSQL is an open source object-relational database system that uses and extends the SQL language combined with many features that safely store and scale the most complicated data workloads.

PostgreSQL comes with many features aimed to help developers build applications, administrators to protect data integrity and build fault-tolerant environments, and help you manage your data no matter how big or small the dataset.

Being open source, it can be used for free, and PostgreSQL is very extensible. For example: Defining your own data types, build out custom functions, even write code from different programming languages without recompiling your database!

PostgreSQL tries to conform with the SQL standard where such conformance does not contradict traditional features or could lead to poor architectural decisions.

This test contains 15 items that seek to determine the candidate’s general knowledge of PostgreSQL’s concepts and tools, and are spread into categories:

  • Joins, Queries
  • Grouping, Aggregate Functions, HAVING Clause
  • Subqueries, EXISTS, IN Operators
  • Miscellaneous: Ranking Functions, Foreign Key, UNION Operator, NULLs

We believe that this setup is one of the most reliable and thorough assessments available out in the market and our PostgreSQL experts are continually keeping the test up to current standards.