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:
When you are writing an INSERT statement in T-SQL, the column list is usually optional.
Why would including it be a good idea? When would it ever be required (i.e. not optional)?
Answer:
2021-03-30
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: Query Performance Level: Medium
Question:
In SQL Server a column that is defined with a bit data type can only have the values 0, or 1, or it can be NULL if the column allows it.
Given such a small number of possible values, are bit columns ever useful in indexes? Can you give an example of when they might or might not be useful?
2021-03-26
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:
When you are writing a CREATE TABLE statement to define a new table, after each column, you can write NULL or NOT NULL, but doing that is optional.
Why is it a good practice to include it, and what happens if you leave it out? Are the columns defined as NULL or as NOT NULL? Are there any exceptions to this?
2021-03-25
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: Security Level: Medium
Question:
I have an application that connects to the database as a user called ReaderApp. The only role that ReaderApp has been added to is db_datareader. The application was previously only using SELECT statements to read data that was required.
2021-03-19
Many clients hire me to carry out job interviews on their behalf. If they’re hiring someone for a data-related role, they want to make sure they’re hiring the right person. That usually means two things:
I can’t help with the first one. If I’ve worked with the client for a long time, I might have a pretty good idea but ultimately, that’s something the client needs to decide.
2021-03-18
