Twenty new quizzes are now available on AnyTest, with 400 questions and explanations. This collection focuses on small topics that are easy to overlook: how a heap handles replacement, why a SQL aggregate returns NULL, or what happens when an object is cloned.

Each quiz has a bank of 20 questions. An attempt draws 10, with a practice target of 8 correct answers. Use the explanations on the results page to understand the rule behind an answer, then try another selection.

Python and data tools: work through the edge cases

Compare heappushpop with heapreplace, explore signed Counter values, distinguish repeated local times with zoneinfo, and follow ExitStack cleanup order. The Pandas quiz focuses on merge_asof direction and tolerance; NumPy practice covers insertion boundaries and the meaning of sorter.

SQL, JavaScript and command-line tools

Choose one row per group with PostgreSQL DISTINCT ON, distinguish subtotal NULLs with GROUPING, and read jsonb containment correctly. Other quizzes cover SQLite affinity, JavaScript cloning and property descriptors, jq filtering, and Git pathspec rules.

Six more quizzes in German, Spanish and Russian

German: conditional calculations with SUMMENPRODUKT and the difference between Git's index and working tree.

Spanish: Python positional-only and keyword-only parameters, plus repeated query keys and encoding with URLSearchParams.

Russian: Excel АГРЕГАТ with errors and hidden rows, and PostgreSQL FILTER for conditional aggregation.

Choose a topic, not a whole syllabus

The collection contains 14 English, 2 German, 2 Spanish and 2 Russian quizzes. Questions use small examples and focused scenarios rather than attempting to cover an entire programming language or tool. These are original practice exercises, not official certification exams.

Start with a feature you use at work but would hesitate to explain. After the attempt, review the reasoning and compare the cases that behave differently.