SQL Server, like many relational database management systems, has specific limitations that developers need to be aware of when designing and implementing database solutions. One such limitation is the maximum number of expressions that can be specified in the SELECT list of a query. This limit is set at 4096…
Generating Empty GUIDs
12. 4. 2024
In SQL Server, a Globally Unique Identifier (GUID) is a 16-byte binary data type that is commonly used to uniquely identify records in a database. The UNIQUEIDENTIFIER data type in SQL Server is equivalent to a GUID, and there are occasions where you might need to generate an empty GUID,…
Understanding Sparse Columns
9. 4. 2024
Sparse columns in SQL Server are an intriguing feature designed to optimize storage for columns that contain a significant amount of NULL values. Introduced in SQL Server 2008, sparse columns offer a way to store nulls efficiently, consuming no storage space for NULL values in a column. This feature can…
SQL Server 2022 enhances its JSON capabilities with the JSON_OBJECT() function, providing a streamlined approach to transforming SQL query results into JSON format directly within SQL queries. This functionality is invaluable for developers working in environments where SQL Server interacts with web services, applications, or systems that consume or produce…
In the vast world of SQL Server, data integrity is paramount. One critical component in maintaining this integrity is the Suspect Pages Table, a feature many database administrators (DBAs) may encounter but not fully understand. This table, an often-overlooked aspect of SQL Server’s system databases, plays a vital role in…
There are various options on how to save hierarchical data in SQL Server. This article is an overview of them demonstrating their usage on a simple dataset of employees and their managers. I will extend this article when a new option will be available or if you will advise it…
There isn’t built-in support for working with hierarchies in the SQL Server except for the hierarchyid data type. This means that we should solve most of the hierarchical data processing tasks using the old-school portfolio of standard T-SQL language. One of these tasks is a simple conversion of hierarchical paths…
Objects like tables or views can be referenced using the dot (.) notation based on this pattern: [{server}].[{database}].[{schema}].[{object}], e.g. [MyServer1].[MyDatabase1].[dbo].[MyTable1]. One will expect that this sequence should go from right to left and parts can’t be skipped. But we can have much more fun with it in the reality. When…
Generate Array of Values in FOR JSON
23. 1. 2022
There is quite sustainable support for working with JSON format in SQL Server since the 2016 version. But it’s tricky time-to-time to do more complex things, especially building more complex JSON documents from tabular data format. One of these things is how to build an array of values, e.g. we…
Practical Tally Table to WHILE Comparison (Generating Calendar) The “Tally table” is a well-known concept not only in the SQL Server world but in all set-based (relational) database engines. I don’t want to repeat some basic or go much deep into it. You can do it on your own starting…