This is a post in the SQL Interview series. These aren’t trick or gotcha questions, they’re just questions designed to scope out a candidate’s knowledge around SQL Server and Azure SQL Database.
Section: Developer Level: Intro
Question:
You are writing a function that needs to process UTF-8 data. It takes one input parameter named @ValueToProcess that varies in length.
Which data type should you use for the @ValueToProcess parameter?
Answer:
2025-05-08
This is a post in the SQL Interview series. These aren’t trick or gotcha questions, they’re just questions designed to scope out a candidate’s knowledge around SQL Server and Azure SQL Database.
Section: Developer Level: Medium
Question:
You have a value in a variable named @NewValue. The data type is varchar(20).
You want to check if the value in the string is an integer and could be cast to an integer.
2025-05-06
This is a post in the SQL Interview series. These aren’t trick or gotcha questions, they’re just questions designed to scope out a candidate’s knowledge around SQL Server and Azure SQL Database.
Section: Developer Level: Intro
Question:
You want to call a procedure that counts the number of customers in a particular city.
You use the following code:
DECLARE @NumberOfCustomers int;
EXEC dbo.GetNumberOfCustomers
@City = N'Brisbane',
@NumberOfCustomers = @NumberOfCustomers;
SELECT @NumberOfCustomers;
No matter which city name you pass in the code, the selected count is NULL.
2025-05-04
This is a post in the SQL Interview series. These aren’t trick or gotcha questions, they’re just questions designed to scope out a candidate’s knowledge around SQL Server and Azure SQL Database.
Section: Developer Level: Medium
Question:
You have a series of very similar SQL queries in an application.
You notice that one of them includes an OPTION LABEL clause.
What would this be used for?
Answer:
OPTION LABEL allows you to apply a label to an instance of a query. That then makes it easy to trace executions of the query using tools like Extended Events or SQL Server Profiler.
2025-05-02
This is a post in the SQL Interview series. These aren’t trick or gotcha questions, they’re just questions designed to scope out a candidate’s knowledge around SQL Server and Azure SQL Database.
Section: Administrator Level: Medium
Question:
Your team is considering a design where a small number of tables would each have a very large number of columns.
One developer has suggested making the columns SPARSE where another has suggested just making them NULLable.
2025-04-28
This is a post in the SQL Interview series. These aren’t trick or gotcha questions, they’re just questions designed to scope out a candidate’s knowledge around SQL Server and Azure SQL Database.
Section: Development Level: Advanced
Question:
You have a table in your database that contains six columns that are defined with the text data type.
When you run checks on your database, these columns are often flagged with deprecation warnings, and so you change each column as follows:
2025-04-25
This is a post in the SQL Interview series. These aren’t trick or gotcha questions, they’re just questions designed to scope out a candidate’s knowledge around SQL Server and Azure SQL Database.
Section: Development Level: Medium
Question:
You have a column in your database that is defined as char(20). Whenever you query it, 20 characters are returned, with space padding any unused characters.
An administrator has suggested applying ROW compression to the table, to save space and improve performance.
2025-04-23
This is a post in the SQL Interview series. These aren’t trick or gotcha questions, they’re just questions designed to scope out a candidate’s knowledge around SQL Server and Azure SQL Database.
Section: Administration Level: Medium
Question:
A developer in your team has suggested applying PAGE compression to all tables and indexes in your application database.
You are concerned that doing so might impact performance, and that ROW compression might be better.
2025-04-19
This is a post in the SQL Interview series. These aren’t trick or gotcha questions, they’re just questions designed to scope out a candidate’s knowledge around SQL Server and Azure SQL Database.
Section: Administration Level: Advanced
Question:
You need to write code to avoid the impact of indexes during data loads.
You could DROP and CREATE the indexes, or you could DISABLE and REBUILD them.
Which should you choose and why? How would the performance compare between the two options?
2025-04-15
This is a post in the SQL Interview series. These aren’t trick or gotcha questions, they’re just questions designed to scope out a candidate’s knowledge around SQL Server and Azure SQL Database.
Section: Administration Level: Medium
Question:
You are using linked servers to refer to tables in a database on another server.
You are concerned that the name of the server appears in three-part table names throughout your code. If the linked server name changes, it would be very messy to locate and correct all references to it.
2025-04-13