SQL Practice Tests 2026, 120 Questions, Verified Answers

This course contains the use of artificial intelligence.

Here is what that means in practice, and why it is the reason to take this

one rather than another. Every question in these tests is built around a small

set of tables and one query. When the test was assembled, that query was

executed on two independent engines, SQLite and DuckDB, and the option marked

correct is the result set they both returned. A question whose stated answer

disagreed with the engines could not be published, the build refuses it. A

query on which the two engines disagreed could not be published either, because

that is a question about a dialect wearing the costume of a question about SQL.

Those two checks are the whole point of the product.

If you have taken SQL practice tests before, you already know the two

complaints. The answer key is wrong often enough that you stop trusting it, and

half the questions turn out to be about one vendor's engine even though the

title said SQL. Neither can happen here. Each explanation ends with the exact

result both engines returned, and any query the two of them answered

differently was thrown out during the build rather than argued about in the

reviews.

What is inside

Four full practice tests, 120 questions, forty-five minutes and a pass mark

of 70 percent each.

Every question runs against one of three small tables you will get to know

quickly, a shop with customers and orders, a company with departments and

employees, and a table of exam marks. They are deliberately small, and they are

deliberately awkward. There is an order whose customer does not exist, an

employee with no department, a department with no employees, a mark that was

never recorded and a pair of identical salaries. Those five rows are where the

interesting questions live, because they are where real tables break real

queries.

Questions are spread over seven blocks. Selecting, filtering and sorting.

Joins, including the outer joins and the anti join. Grouping and aggregation.

NULL, CASE and the set operators. Subqueries and common table expressions.

Window functions. Strings, numbers and type conversion. Every question is

tagged with its block, so the result screen tells you which one is costing you

the marks instead of leaving you to guess.

Each answer, right or wrong, carries its own explanation. Not one comment

for the question, one for every option, saying why that particular option is

wrong and which confusion usually produces it.

What you will not find here

No question depends on which database you use at work. Nothing about

PL/SQL, nothing about T-SQL, no vendor specific date function and no engine

specific string function. If a query behaved differently on the two engines it

was cut, which means what you learn here transfers to Postgres, MySQL, SQL

Server, Oracle and SQLite alike.

You will also not find the same question twice. The build rejects a repeated

query outright, which is the second thing reviewers on this shelf complain

about.

How to use it

Sit a test under exam conditions first, forty-five minutes, no database

open. Read every explanation afterwards, including the ones you got right,

because guessing correctly and knowing are not the same thing. Then rerun the

queries yourself. The tables fit in a screen and rebuild in a second on any

engine you like.

Who this is for

Anyone facing a SQL screening test for a data analyst, data engineer,

analytics or backend role, and anyone who writes SQL most weeks and suspects

that a few of the habits are cargo cult. If you have ever been surprised by

what NOT IN does when the subquery returns a NULL, or by a left join that

silently turned into an inner join, this is aimed squarely at you.