Azure-Sql-Db

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 need to add a new column to a table. A developer insists that the column needs to be inserted into the middle of the existing table, not as a new column at the end.

2025-03-21

I showed how identity columns are a special type of constraint. They can be int or bigint. Both work just fine. What you might need to know though, is the last value inserted automatically by SQL Server. @@IDENTITY For a long time, SQL Server only had a single option for this. It was the @@IDENTITY value. The problem was that it could give you a value different to what you were looking for.

2025-03-20

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 add a computed column to an existing table. You then select from the table. When is the value of the computed column calculated i.e., when the value is inserted or updated, or when the value is selected?

2025-03-19

One of the most popular courses that we used to run in person was a SQL Server Administration course. Yesterday, I recently finished converting the course to an online format, and it was a big job. I’ve had many people asking if we had this type of course. Administration is such an important skill. Not just a single version course We were also determined to stay with our tradition of making multi-version courses.

2025-03-18

In the previous post, I talked about how you could add default values for columns. One special type of default value is called an IDENTITY constraint. These columns are one way to achieve automatic numbering in a column. There are many pros and cons about using these but at this point, I want to make sure you know how to use them. The main difference from other columns is that you don’t put them in your INSERT statements.

2025-03-18

Default constraints allow us to automatically provide values for columns when: we don’t supply them ourselves they are marked as NOT NULL so they are required When you’re building an INSERT statement, you don’t have to give values for all columns. Columns that are declared as NULL aren’t mandatory, so you don’t have to supply those columns at all. Those columns can just be NULL. But if you have a column that is declared as NOT NULL, so it requires a value, but you haven’t supplied it in the INSERT statement, then a default constraint can provide the value.

2025-03-16

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 need to add additional columns to a table. You are concerned that you do not want to lock the table for long periods. You plan to avoid any operation that would rewrite every row i.

2025-03-15

Prior to SQL Server 2008, we could only insert a single row at a time. SQL Server 2008 added the ability to have multiple rows of data in the VALUES clause. Each row is created from what are typically called row constructors. In the example above, I’m inserting 3 rows into the Cinema Groups table. The syntax allows for up to 1000 rows to be inserted at once. Before you get to that number of rows though, you might exceed the maximum allowable length for a T-SQL statement, if you have a lot of columns, each with a lot of data.

2025-03-14

Our free SDU Tools for developers and DBAs, now includes a very large number of tools, with procedures, functions, and views. Users that are new to working with sequences often don’t have simple options for resetting them back to a specific value. Many business intelligence ETL or ELT processes need to have a way to do this. So we added a tool that can help. It’s called ResetSequence. The procedure takes three parameters.

2025-03-13

To insert new rows into a table, you will mostly use the INSERT statement. In the example above, I’ve inserted one row into the dbo.CinemaGroups table. There are a few aspects to this statement. First, you should always use two-part names for the table i.e., use dbo.CinemaGroups not just CinemaGroups. Second, there is an optional INTO keyword for INSERT statements. You can say INSERT INTO dbo.CinemaGroups. While I’m generally pretty pedantic about these things, I can’t see any value that the word INTO adds here and I don’t use it.

2025-03-12