These are three sample questions from Bryq’s SQL assessment, a technical test for hiring data analysts, back-end developers, and database specialists. The full assessment covers three levels: beginner, intermediate, and advanced, from core keywords to joins and built-in functions. Questions test both SQL knowledge and the ability to predict what a query returns, with four options and one correct answer each.
Beginner
Question
Which SQL keyword is used to retrieve only unique values from a column?
Select your answer
`DISTINCT`
`EXCLUDE`
`FILTER`
`LIMIT`
WHY IS THIS THE CORECT ANSWER
SELECT DISTINCT removes duplicate rows from the result set, so only unique values are returned.
Intermediate
Question
Which type of SQL `JOIN` returns all records from the left table and only the matching records from the right table?
Select your answer
`LEFT JOIN`
`RIGHT JOIN`
`FULL JOIN`
`INNER JOIN`
WHY IS THIS THE CORECT ANSWER
A LEFT JOIN keeps every row from the left table and fills columns from the right table with NULL where there is no match. An INNER JOIN would drop the unmatched left rows.
Advanced
Question
What will the following SQL query return if a record has `NULL` in both the `phone` and `email` columns?
`SELECT COALESCE(phone, email, 'No contact') FROM customers;`
Select your answer
`No contact`
`Error`
`NULL`
`0`
