| 1 | How do you configure and use raw SQL queries alongside LINQ in EF Core when a complex query is difficult or inefficient to express in LINQ? .NET › Entity Framework Core & Data Access | .NET | Entity Framework Core & Data Access | Intermediate |
| 2 | How should a team decide between using an ORM like Eloquent or Doctrine versus writing raw SQL queries directly for a specific, particularly complex or performance sensitive part of an application? PHP › Eloquent ORM & Doctrine ORM | PHP | Eloquent ORM & Doctrine ORM | Advanced |
| 3 | What is a subquery in SQL Server, and how is it typically used within a larger query? SQL Server › Subqueries | SQL Server | Subqueries | Beginner |
| 4 | How does Sequelize define models and relationships for a relational (SQL) database in Node.js? Node.js › Databases & ORMs (MongoDB/Mongoose, SQL/Sequelize) | Node.js | Databases & ORMs (MongoDB/Mongoose, SQL/Sequelize) | Intermediate |
| 5 | How do you create an Extended Events session to capture specific long running queries on a production server? SQL Server › SQL Server Profiler & Extended Events | SQL Server | SQL Server Profiler & Extended Events | Intermediate |
| 6 | What are common mistakes developers make when writing subqueries that can lead to incorrect results or poor performance? SQL Server › Subqueries | SQL Server | Subqueries | Intermediate |
| 7 | How does the SQL Server query optimizer typically handle and potentially transform a subquery internally when generating an execution plan? SQL Server › Subqueries | SQL Server | Subqueries | Advanced |
| 8 | What is an index in SQL Server, and how does it help speed up queries? SQL Server › Indexes | SQL Server | Indexes | Beginner |
| 9 | What is a user defined function in SQL Server, and why would you create one instead of repeating the same logic in multiple queries? SQL Server › User Defined Functions | SQL Server | User Defined Functions | Beginner |
| 10 | How does SQL Server compile and cache execution plans for stored procedures, and how does this affect performance compared to ad hoc queries? SQL Server › Stored Procedures & Functions | SQL Server | Stored Procedures & Functions | Advanced |
| 11 | What is SQL injection, and how does using parameterized queries in Node.js prevent it? Node.js › Databases | Node.js | Databases | Intermediate |
| 12 | What is the difference between the JSON_VALUE and JSON_QUERY functions? SQL Server › JSON Support in SQL Server | SQL Server | JSON Support in SQL Server | Beginner |
| 13 | How do you convert a JSON array stored in a column into a relational table format that can be queried like normal rows? SQL Server › JSON Support in SQL Server | SQL Server | JSON Support in SQL Server | Intermediate |
| 14 | How do you view the top resource consuming queries captured by Query Store? SQL Server › Query Store | SQL Server | Query Store | Beginner |
| 15 | What is the difference between a correlated and a non correlated subquery? SQL Server › Subqueries | SQL Server | Subqueries | Beginner |
| 16 | What tools or queries can you use to monitor the health and effectiveness of a columnstore index over time? SQL Server › Columnstore Indexes | SQL Server | Columnstore Indexes | Intermediate |
| 17 | What is the difference between using EXISTS and IN when checking for the presence of related data with a subquery? SQL Server › Subqueries | SQL Server | Subqueries | Intermediate |
| 18 | How do you use a subquery within the SELECT list to calculate a related aggregate value alongside each row of the outer query? SQL Server › Subqueries | SQL Server | Subqueries | Intermediate |
| 19 | How would you diagnose and resolve a blocking problem where many queries are waiting on a single long running transaction? SQL Server › Isolation & Locking | SQL Server | Isolation & Locking | Advanced |
| 20 | How would you rewrite a slow correlated subquery as an equivalent, potentially faster JOIN based query? SQL Server › Subqueries | SQL Server | Subqueries | Advanced |
| 21 | How would you read a deadlock graph to identify the exact queries and resources that caused a specific deadlock? SQL Server › Deadlocks | SQL Server | Deadlocks | Advanced |
| 22 | What is an indexed view, and how can it improve the performance of complex, frequently run queries? SQL Server › Views | SQL Server | Views | Intermediate |
| 23 | What are the differences in how a hash index and a memory optimized nonclustered index handle range queries and equality lookups? SQL Server › Hash Indexes & Hash Join Operations | SQL Server | Hash Indexes & Hash Join Operations | Intermediate |
| 24 | What is a common table expression, and why would you use one instead of a subquery? SQL Server › Common Table Expressions (CTEs) | SQL Server | Common Table Expressions (CTEs) | Beginner |
| 25 | How do you define multiple common table expressions within a single query? SQL Server › Common Table Expressions (CTEs) | SQL Server | Common Table Expressions (CTEs) | Beginner |
| 26 | What is the difference between a LEFT JOIN and a RIGHT JOIN? SQL Server › Joins | SQL Server | Joins | Beginner |
| 27 | How do you filter the results of a grouped query based on an aggregated value, such as only showing customers who spent more than a certain amount? SQL Server › Aggregate Functions & GROUP BY | SQL Server | Aggregate Functions & GROUP BY | Intermediate |
| 28 | What is a recursive common table expression, and what kind of problems is it commonly used to solve? SQL Server › Common Table Expressions (CTEs) | SQL Server | Common Table Expressions (CTEs) | Intermediate |
| 29 | How do you find rows that exist in one table but have no matching row in another table using a join? SQL Server › Joins | SQL Server | Joins | Intermediate |
| 30 | Can a common table expression be used inside an UPDATE, DELETE, or MERGE statement, and how does that work? SQL Server › Common Table Expressions (CTEs) | SQL Server | Common Table Expressions (CTEs) | Advanced |
| 31 | What is the difference between IEnumerable<T>, IQueryable<T>, and List<T>, and how does choosing the wrong one hurt performance against a database? C# › LINQ | C# | LINQ | Intermediate |
| 32 | What is database normalization, and what specific problems can over-normalization or under-normalization cause? Node.js › Databases | Node.js | Databases | Intermediate |
| 33 | What is the difference between a one-to-many and a many-to-many relationship in a relational database, and how is each modeled? Node.js › Databases | Node.js | Databases | Intermediate |
| 34 | What are the most important Entity Framework Core best practices for building performant, reliable data access code? .NET › Entity Framework Core & Data Access | .NET | Entity Framework Core & Data Access | Advanced |
| 35 | What is database indexing, and how does an index improve query performance in a Node.js application's database layer? Node.js › Databases | Node.js | Databases | Advanced |