Practice test

SQL Interview Mock 3

Mock 3 of the SQL Interview Test Series: 15 questions on SQL building blocks in SQL Server (T-SQL): self joins, table aliases and error 4104, AVG over an int column, COUNT(*) vs COUNT(1), NULLIF and empty strings, CTE scope and error 208, EXISTS, LAG with a default and PARTITION BY, UNION rules, DEFAULT vs an explicit NULL, which WHERE clauses can seek a composite index, SELECT * in a view after the table changes, nested transactions, TOP WITH TIES, and deleting duplicates with ROW_NUMBER. Mixed formats (query output, find-the-bug, pick-the-query, theory, multi-select and numeric), each with a full teaching explanation after you submit. Included in Full Access.

Questions

15

Time

20 min

Right answer

+1

Wrong answer

0

15 marks in all · pass mark 9