| 1 | How do filtered indexes work, and what specific scenarios benefit most from using one? SQL Server › Indexes | SQL Server | Indexes | Advanced |
| 2 | How do you identify unused or duplicate indexes that might be safely removed to improve write performance? SQL Server › Indexes | SQL Server | Indexes | Intermediate |
| 3 | What are delta stores and rowgroups in the context of columnstore indexes, and how do they affect performance over time? SQL Server › Columnstore Indexes | SQL Server | Columnstore Indexes | Advanced |
| 4 | What kinds of workloads benefit the most from columnstore indexes, and which workloads should avoid them? SQL Server › Columnstore Indexes | SQL Server | Columnstore Indexes | Intermediate |
| 5 | Can you create indexes on a temporary table, and how does this compare to indexing options available for table variables? SQL Server › Temporary Tables & Table Variables | SQL Server | Temporary Tables & Table Variables | Intermediate |
| 6 | What is a covering index, and how does it help avoid an expensive lookup operation? SQL Server › Indexes | SQL Server | Indexes | Intermediate |
| 7 | What are Global Secondary Indexes and Local Secondary Indexes in DynamoDB? AWS › Amazon DynamoDB | AWS | Amazon DynamoDB | Intermediate |
| 8 | What are the memory and performance tradeoffs of adding RedisSearch indexes to a large existing dataset in Redis? Redis › RedisSearch (Full Text Search) | Redis | RedisSearch (Full Text Search) | Advanced |
| 9 | How can you properly optimize sqflite query performance for a genuinely large dataset using database indexes, and what genuine tradeoffs come together with actually adding an index to a given specific table? Flutter › SQLite & Local Databases (sqflite) | Flutter | SQLite & Local Databases (sqflite) | Advanced |
| 10 | What is an index in SQL Server, and how does it help speed up queries? SQL Server › Indexes | SQL Server | Indexes | Beginner |
| 11 | What is the difference between a clustered index and a nonclustered index? SQL Server › Indexes | SQL Server | Indexes | Beginner |
| 12 | How do you decide which columns to choose, and in what order, when creating a composite index covering multiple columns? SQL Server › Indexes | SQL Server | Indexes | Intermediate |
| 13 | How does index fragmentation happen over time, and how do you address it? SQL Server › Indexes | SQL Server | Indexes | Advanced |
| 14 | What is a columnstore index in SQL Server, and how is it different from a regular index? SQL Server › Columnstore Indexes | SQL Server | Columnstore Indexes | Beginner |
| 15 | What is the difference between a clustered columnstore index and a nonclustered columnstore index? SQL Server › Columnstore Indexes | SQL Server | Columnstore Indexes | Beginner |
| 16 | What is a hash index, and how is it different from the more common B-tree index used for regular disk based tables? SQL Server › Hash Indexes & Hash Join Operations | SQL Server | Hash Indexes & Hash Join Operations | Beginner |
| 17 | In what situations does SQL Server's query optimizer typically prefer a hash join over a nested loop join or a merge join? SQL Server › Hash Indexes & Hash Join Operations | SQL Server | Hash Indexes & Hash Join Operations | Intermediate |
| 18 | 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 |
| 19 | How would you decide whether to use a clustered columnstore index or a traditional partitioned rowstore table for a very large historical sales table? SQL Server › Columnstore Indexes | SQL Server | Columnstore Indexes | Advanced |
| 20 | How would you troubleshoot a query that is unexpectedly using a slow hash join when a much faster index seek and nested loop join should be possible? SQL Server › Hash Indexes & Hash Join Operations | SQL Server | Hash Indexes & Hash Join Operations | Advanced |
| 21 | What is a hash join, and how does SQL Server use it to combine two tables? SQL Server › Hash Indexes & Hash Join Operations | SQL Server | Hash Indexes & Hash Join Operations | Beginner |
| 22 | How does columnstore compression work, and why does it typically achieve much higher compression ratios than regular row based storage? SQL Server › Columnstore Indexes | SQL Server | Columnstore Indexes | Intermediate |
| 23 | 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 |
| 24 | How does the BUCKET_COUNT setting affect the performance of a hash index on a memory optimized table? SQL Server › Hash Indexes & Hash Join Operations | SQL Server | Hash Indexes & Hash Join Operations | Intermediate |
| 25 | What happens when a hash join does not have enough memory available to build its hash table entirely in memory, and how does this affect performance? SQL Server › Hash Indexes & Hash Join Operations | SQL Server | Hash Indexes & Hash Join Operations | Advanced |
| 26 | What is the difference between VARCHAR and NVARCHAR, and when should you choose one over the other? SQL Server › Data Types & Schema Design | SQL Server | Data Types & Schema Design | Beginner |
| 27 | What is full text search in SQL Server, and how is it different from a regular LIKE search? SQL Server › Full Text Search | SQL Server | Full Text Search | Beginner |
| 28 | How do you create a full text index on a table so you can use full text search functions? SQL Server › Full Text Search | SQL Server | Full Text Search | Beginner |
| 29 | What is In-Memory OLTP in SQL Server, and what performance benefit does it provide? SQL Server › In-Memory OLTP (Memory-Optimized Tables) | SQL Server | In-Memory OLTP (Memory-Optimized Tables) | Beginner |
| 30 | What is table partitioning in SQL Server, and what problem does it help solve for very large tables? SQL Server › Partitioning | SQL Server | Partitioning | Beginner |
| 31 | What is an execution plan in SQL Server, and how does it help you understand query performance? SQL Server › Query Optimization & Plans | SQL Server | Query Optimization & Plans | Beginner |
| 32 | What is the difference between a table scan and an index seek in an execution plan, and why does this distinction matter for performance? SQL Server › Query Optimization & Plans | SQL Server | Query Optimization & Plans | Beginner |
| 33 | How do you correctly combine WHERE and HAVING in the same query to filter both individual rows and grouped results? SQL Server › Aggregate Functions & GROUP BY | SQL Server | Aggregate Functions & GROUP BY | Intermediate |
| 34 | How is a unique constraint different from a primary key constraint, and when would you use one instead of the other? SQL Server › Constraints (Primary Key, Foreign Key, Check & Unique) | SQL Server | Constraints (Primary Key, Foreign Key, Check & Unique) | Intermediate |
| 35 | What is the performance impact of using a cursor compared to a set based operation on a large table, and why does this difference occur? SQL Server › Cursors | SQL Server | Cursors | Intermediate |
| 36 | How do computed columns work in SQL Server, and what are some practical use cases for them? SQL Server › Data Types & Schema Design | SQL Server | Data Types & Schema Design | Intermediate |
| 37 | How do you perform a proximity search using full text search, finding rows where two words appear near each other? SQL Server › Full Text Search | SQL Server | Full Text Search | Intermediate |
| 38 | What SQL Server edition requirements exist for using In-Memory OLTP features? SQL Server › In-Memory OLTP (Memory-Optimized Tables) | SQL Server | In-Memory OLTP (Memory-Optimized Tables) | Intermediate |
| 39 | How does partition elimination improve query performance for a partitioned table? SQL Server › Partitioning | SQL Server | Partitioning | Intermediate |
| 40 | How do outdated or missing statistics affect the query optimizer's ability to choose an efficient execution plan? SQL Server › Query Optimization & Plans | SQL Server | Query Optimization & Plans | Intermediate |
| 41 | What are the most common causes of poor query performance that you should check first when troubleshooting a slow query? SQL Server › Query Optimization & Plans | SQL Server | Query Optimization & Plans | Intermediate |
| 42 | What is a schema bound view, and what specific benefit does the WITH SCHEMABINDING option provide? SQL Server › Views | SQL Server | Views | Intermediate |
| 43 | What is an indexed view, and how can it improve the performance of complex, frequently run queries? SQL Server › Views | SQL Server | Views | Intermediate |
| 44 | How do you rank and sort full text search results by their relevance to the search query? SQL Server › Full Text Search | SQL Server | Full Text Search | Advanced |
| 45 | How does SQL Server's query optimizer decide which physical join algorithm, such as nested loops, merge join, or hash join, to actually use for a given query? SQL Server › Joins | SQL Server | Joins | Advanced |
| 46 | What are the performance considerations and limitations of querying JSON data stored as text compared to using normalized relational columns? SQL Server › JSON Support in SQL Server | SQL Server | JSON Support in SQL Server | Advanced |
| 47 | How would you troubleshoot a linked server query that is running much slower than expected? SQL Server › Linked Servers | SQL Server | Linked Servers | Advanced |
| 48 | What performance considerations should you keep in mind when using MERGE against very large source and target tables? SQL Server › Merge Statement (Upsert) | SQL Server | Merge Statement (Upsert) | Advanced |
| 49 | What requirements must be satisfied for the ALTER TABLE SWITCH PARTITION operation to work correctly when moving data between tables? SQL Server › Partitioning | SQL Server | Partitioning | Advanced |
| 50 | What performance considerations should you keep in mind when using PIVOT or UNPIVOT on very large datasets? SQL Server › Pivoting & Unpivoting Data | SQL Server | Pivoting & Unpivoting Data | Advanced |
| 51 | How would you use query hints to influence the optimizer's behavior when you have determined the default execution plan is genuinely suboptimal? SQL Server › Query Optimization & Plans | SQL Server | Query Optimization & Plans | Advanced |
| 52 | How does an XML index improve query performance against large or frequently queried XML columns? SQL Server › XML Data Type & Querying | SQL Server | XML Data Type & Querying | Advanced |
| 53 | What design changes can you make to application code and database access patterns to reduce the frequency of deadlocks? SQL Server › Deadlocks | SQL Server | Deadlocks | Advanced |